Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

Type about:support in the address bar and press Enter. Under the main banner, press the button; Copy Text To Clipboard.. Then in the reply box at the bottom of this page, do a right click in the box and select Paste. This will show us your system details. No Personal Information Is Collected.

Update your Flash Player Version 19.0.0.185
https://www.adobe.com/products/flashplayer/distribution3.html Note: Windows users must download the “Internet Explorer” and “Plugin-based browsers” installers.

Note: Edge on Win10 does not use ActiveX version but its own Flash.

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

Separate Issue; Your System Details shows;

Installed Plug-ins

Adobe Shockwave for Director Netscape plug-in, version 12.1.4.154 Adobe Shockwave for Director Netscape plug-in, version 12.1.3.153
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

Note: Edge on Win10 does not use ActiveX version but its own Flash.

Flash: Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac

Then reinstall the latest version.

Flash Player Version 19.0.0.185
https://www.adobe.com/products/flashplayer/distribution3.html Note: Windows users must download the “Internet Explorer” and “Plugin-based browsers” installers.

You can skip pages in the tab history by opening the tab history list. You can hold the left mouse button on the Back button to open this drop-down list.

Application Basics

Name: Firefox Version: 39.0 Build ID: 20150630154324 Update Channel: release User Agent: Mozilla/5.0 (Windows NT 6.1; rv:39.0) Gecko/20100101 Firefox/39.0 Multiprocess Windows: 0/1 (default: false)

Crash Reports for the Last 3 Days

All Crash Reports (including 2 pending crashes in the given time range)

Extensions

Name: Easy YouTube Video Downloader Version: 7.0 Enabled: false ID: {c0c9a2c7-2e5c-4447-bc53-97718bc91e1b}

Name: Lightbeam Version: 1.2.1.1-signed Enabled: false ID: jid1-F9UJ2thwoAm5gQ@jetpack

Name: Logitech SetPoint Version: 6.5 Enabled: false ID: {F003DA68-8256-4b37-A6C4-350FA04494DF}

Name: New Tab Homepage Version: 0.4.3.1-signed Enabled: false ID: {66E978CD-981F-47DF-AC42-E3CF417C1467}

Name: Tabbrowser Preferences Version: 3.0.1-signed Enabled: false ID: {9b9d2aaa-ae26-4447-a7a1-633a32b19ddd}

Name: uBlock Version: 0.9.1.0.1-signed Enabled: false ID: {2b10c1c8-a11f-4bad-fe9c-1c11e82cac42}

Graphics

Adapter Description: NVIDIA GeForce GTX 560 Adapter Drivers: nvd3dum,nvwgf2um,nvwgf2um Adapter RAM: 1024 Asynchronous Pan/Zoom: none Device ID: 0x1201 DirectWrite Enabled: false (6.2.9200.17292) Driver Date: 6-17-2015 Driver Version: 10.18.13.5330 GPU #2 Active: false GPU Accelerated Windows: 0/1 Basic (OMTC) Subsys ID: 14613842 Vendor ID: 0x10de windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0

Important Modified Preferences

accessibility.typeaheadfind.flashBar: 0 browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.smart_size_cached_value: 358400 browser.cache.disk.smart_size.first_run: false browser.cache.disk.smart_size.use_old_max: false browser.cache.frecency_experiment: 2 browser.download.importedFromSqlite: true browser.download.useDownloadDir: false browser.places.smartBookmarksVersion: 7 browser.search.useDBForOrder: true browser.sessionstore.resume_from_crash: false browser.sessionstore.upgradeBackup.latestBuildID: 20150630154324 browser.startup.homepage: http://www.google.com/ browser.startup.homepage_override.buildID: 20150630154324 browser.startup.homepage_override.mstone: 39.0 dom.mozApps.used: true dom.w3c_touch_events.expose: false extensions.lastAppVersion: 39.0 font.internaluseonly.changed: false gfx.direct3d.last_used_feature_level_idx: 0 gfx.direct3d.prefer_10_1: true media.gmp-eme-adobe.lastUpdate: 1442515840 media.gmp-eme-adobe.version: 13 media.gmp-gmpopenh264.lastUpdate: 1432089882 media.gmp-gmpopenh264.version: 1.4 media.gmp-manager.buildID: 20150630154324 media.gmp-manager.lastCheck: 1443049107 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.database.lastMaintenance: 1442443687 places.history.expiration.transient_current_max_pages: 64719 places.history.expiration.transient_optimal_database_size: 149917696 plugin.disable_full_page_plugin_for_types: application/pdf,video/x-ms-asf-plugin,application/x-mplayer2,video/x-ms-asf,audio/x-mpegurl plugin.importedState: true print.printer_Canon_Inkjet_MP620_series.print_bgcolor: false print.printer_Canon_Inkjet_MP620_series.print_bgimages: false print.printer_Canon_Inkjet_MP620_series.print_colorspace: print.printer_Canon_Inkjet_MP620_series.print_command: print.printer_Canon_Inkjet_MP620_series.print_downloadfonts: false print.printer_Canon_Inkjet_MP620_series.print_duplex: 0 print.printer_Canon_Inkjet_MP620_series.print_edge_bottom: 0 print.printer_Canon_Inkjet_MP620_series.print_edge_left: 0 print.printer_Canon_Inkjet_MP620_series.print_edge_right: 0 print.printer_Canon_Inkjet_MP620_series.print_edge_top: 0 print.printer_Canon_Inkjet_MP620_series.print_evenpages: true print.printer_Canon_Inkjet_MP620_series.print_footercenter: print.printer_Canon_Inkjet_MP620_series.print_footerleft: &PT print.printer_Canon_Inkjet_MP620_series.print_footerright: &D print.printer_Canon_Inkjet_MP620_series.print_headercenter: print.printer_Canon_Inkjet_MP620_series.print_headerleft: &T print.printer_Canon_Inkjet_MP620_series.print_headerright: &U print.printer_Canon_Inkjet_MP620_series.print_in_color: true print.printer_Canon_Inkjet_MP620_series.print_margin_bottom: 0.5 print.printer_Canon_Inkjet_MP620_series.print_margin_left: 0.5 print.printer_Canon_Inkjet_MP620_series.print_margin_right: 0.5 print.printer_Canon_Inkjet_MP620_series.print_margin_top: 0.5 print.printer_Canon_Inkjet_MP620_series.print_oddpages: true print.printer_Canon_Inkjet_MP620_series.print_orientation: 0 print.printer_Canon_Inkjet_MP620_series.print_page_delay: 50 print.printer_Canon_Inkjet_MP620_series.print_paper_data: 1 print.printer_Canon_Inkjet_MP620_series.print_paper_height: 11.00 print.printer_Canon_Inkjet_MP620_series.print_paper_name: print.printer_Canon_Inkjet_MP620_series.print_paper_size_type: 0 print.printer_Canon_Inkjet_MP620_series.print_paper_size_unit: 0 print.printer_Canon_Inkjet_MP620_series.print_paper_width: 8.50 print.printer_Canon_Inkjet_MP620_series.print_plex_name: print.printer_Canon_Inkjet_MP620_series.print_resolution: 0 print.printer_Canon_Inkjet_MP620_series.print_resolution_name: print.printer_Canon_Inkjet_MP620_series.print_reversed: false print.printer_Canon_Inkjet_MP620_series.print_scaling: 1.00 print.printer_Canon_Inkjet_MP620_series.print_shrink_to_fit: true print.printer_Canon_Inkjet_MP620_series.print_to_file: false print.printer_Canon_Inkjet_MP620_series.print_unwriteable_margin_bottom: 0 print.printer_Canon_Inkjet_MP620_series.print_unwriteable_margin_left: 0 print.printer_Canon_Inkjet_MP620_series.print_unwriteable_margin_right: 0 print.printer_Canon_Inkjet_MP620_series.print_unwriteable_margin_top: 0 print.printer_Canon_MP620_series_Printer.print_bgcolor: false print.printer_Canon_MP620_series_Printer.print_bgimages: false print.printer_Canon_MP620_series_Printer.print_colorspace: print.printer_Canon_MP620_series_Printer.print_command: print.printer_Canon_MP620_series_Printer.print_downloadfonts: false print.printer_Canon_MP620_series_Printer.print_duplex: -1863319549 print.printer_Canon_MP620_series_Printer.print_edge_bottom: 0 print.printer_Canon_MP620_series_Printer.print_edge_left: 0 print.printer_Canon_MP620_series_Printer.print_edge_right: 0 print.printer_Canon_MP620_series_Printer.print_edge_top: 0 print.printer_Canon_MP620_series_Printer.print_evenpages: true print.printer_Canon_MP620_series_Printer.print_footercenter: print.printer_Canon_MP620_series_Printer.print_footerleft: &PT print.printer_Canon_MP620_series_Printer.print_footerright: &D print.printer_Canon_MP620_series_Printer.print_headercenter: print.printer_Canon_MP620_series_Printer.print_headerleft: &T print.printer_Canon_MP620_series_Printer.print_headerright: &U print.printer_Canon_MP620_series_Printer.print_in_color: true print.printer_Canon_MP620_series_Printer.print_margin_bottom: 0.5 print.printer_Canon_MP620_series_Printer.print_margin_left: 0.5 print.printer_Canon_MP620_series_Printer.print_margin_right: 0.5 print.printer_Canon_MP620_series_Printer.print_margin_top: 0.5 print.printer_Canon_MP620_series_Printer.print_oddpages: true print.printer_Canon_MP620_series_Printer.print_orientation: 0 print.printer_Canon_MP620_series_Printer.print_page_delay: 50 print.printer_Canon_MP620_series_Printer.print_paper_data: 1 print.printer_Canon_MP620_series_Printer.print_paper_height: 11.00 print.printer_Canon_MP620_series_Printer.print_paper_name: print.printer_Canon_MP620_series_Printer.print_paper_size_type: 0 print.printer_Canon_MP620_series_Printer.print_paper_size_unit: 0 print.printer_Canon_MP620_series_Printer.print_paper_width: 8.50 print.printer_Canon_MP620_series_Printer.print_plex_name: print.printer_Canon_MP620_series_Printer.print_resolution: -2123890603 print.printer_Canon_MP620_series_Printer.print_resolution_name: print.printer_Canon_MP620_series_Printer.print_reversed: false print.printer_Canon_MP620_series_Printer.print_scaling: 1.00 print.printer_Canon_MP620_series_Printer.print_shrink_to_fit: true print.printer_Canon_MP620_series_Printer.print_to_file: false print.printer_Canon_MP620_series_Printer.print_unwriteable_margin_bottom: 0 print.printer_Canon_MP620_series_Printer.print_unwriteable_margin_left: 0 print.printer_Canon_MP620_series_Printer.print_unwriteable_margin_right: 0 print.printer_Canon_MP620_series_Printer.print_unwriteable_margin_top: 0 privacy.sanitize.migrateFx3Prefs: true privacy.sanitize.timeSpan: 4 privacy.trackingprotection.enabled: true security.warn_viewing_mixed: false storage.vacuum.last.index: 1 storage.vacuum.last.places.sqlite: 1441130300

Important Locked Preferences

JavaScript

Incremental GC: true

Accessibility

Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.8 Version in use: 4.10.8

NSS Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSSMIME Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSSSL Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSUTIL Expected minimum version: 3.19.2 Version in use: 3.19.2

Experimental Features

Also, on some pages (particularly Facebook), all I have to do is move the mouse and a previous page will open.

Have you tried Firefox in Safe Mode?

Yes. Still happens. Also, Amazon is another one of those pages where I can get stuck in the recursive-loop thing.

What are your protection programs?

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Panda AV, Malwarebytes and uBlock add-on (which obviously doesn't run in Safe Mode).

Could it be a flash plug-in issue?

We won't be sure until it stops.

Figured it out. Logitech's Unity software apparently was freaking out and transposing my mouse buttons at random. I uninstalled it. Unfortunately, now my trackball has little functionality and I had to go back to a regular, wired mouse. Since the uninstall and switch, no issues.

That was very good work. Well Done. Contact their support sites and ask questions.