hello, please try to reset firefox and see if this can address the issue...

Hello. Resetting firefox did nt help to solve my problem. I m attaching the screen shot. Please suggest something.

could you also go to firefox > help > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

Reset Firefox to its default state

If you're having major problems which you can't resolve, start fresh with only your essential information. Troubleshooting Information This page contains technical information that might be useful when you're trying to solve a problem. If you are looking for answers to common questions about Firefox, check out our support website. Application Basics Name Firefox Version 24.0 Update History User Agent Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Firefox/24.0 Profile Folder Enabled Plugins about:plugins Build Configuration about:buildconfig Crash Reports about:crashes Memory Use about:memory Extensions Name Version Enabled ID YouTube Downloader Extension 1.0.6 false {78DADB4B-7468-4c1c-8612-00FBF356A9FF} Important Modified Preferences Name Value browser.cache.disk.capacity 358400 browser.cache.disk.smart_size.first_run false browser.cache.disk.smart_size.use_old_max false browser.cache.disk.smart_size_cached_value 358400 browser.places.smartBookmarksVersion 4 browser.startup.homepage_override.buildID 20130910160258 browser.startup.homepage_override.mstone 24.0 extensions.lastAppVersion 24.0 gfx.direct3d.last_used_feature_level_idx 0 network.cookie.prefsMigrated true places.database.lastMaintenance 1381417332 places.history.expiration.transient_current_max_pages 51757 plugin.disable_full_page_plugin_for_types application/pdf plugin.importedState true privacy.sanitize.migrateFx3Prefs true storage.vacuum.last.index 0 storage.vacuum.last.places.sqlite 1381417332 Graphics Adapter Description Intel(R) HD Graphics Adapter Drivers igdumd32 igd10umd32 igd10umd32 Adapter RAM Unknown Device ID 0x0106 Direct2D Enabled true DirectWrite Enabled true (6.2.9200.16571) Driver Date 5-10-2012 Driver Version 8.15.10.2752 GPU #2 Active false GPU Accelerated Windows 1/1 Direct3D 10 Vendor ID 0x8086 WebGL Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote false AzureCanvasBackend direct2d AzureContentBackend direct2d AzureFallbackCanvasBackend cairo JavaScript Incremental GC true Accessibility Activated false Prevent Accessibility 0 Library Versions Expected minimum version Version in use NSPR 4.10 4.10 NSS 3.15.1 Basic ECC 3.15.1 Basic ECC NSSSMIME 3.15.1 Basic ECC 3.15.1 Basic ECC NSSSSL 3.15.1 Basic ECC 3.15.1 Basic ECC NSSUTIL 3.15.1 3.15.1

if the YouTube Downloader Extension 1.0.6 is still present immediately after a firefox reset it might be some sort of adware that hooks into your system. please try to keep it disabled for the moment in firefox > addons > extensions and run a full scan of your system with different security tools like the free version of malwarebytes & adwcleaner.

Troubleshoot Firefox issues caused by malware

Possible solution: if you type about:config in your address bar and search there for browser.startup.homepage, you can check if it has a strange value and change it to a page you'd like.

thank you guys. It solved the problem. :-)

I have this problem too, and I did what you suggested, but I wouldn't recognize a strange value if I saw one, or know what to change it to. Can you please tell me what to change in order to make Firefox work properly again?

What I see is: Preference name status type value browser.startup.homepage user set string about:home browser.startup.homepage_override.buildID user set string 20131025151332 browser.startup.homepage_override.mstone user set string 25.0 services.sync.prefs.sync.browser.startup.homepage default boolean true