<edit> by OP The thumbnail link of the sceenshot did not show , so I will try to add via this website : [https://support.cdn.mozilla.net/media.../2015-05-20-07-36-40-385e91.png

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  http://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked
• https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware

It turns out that it was was caused by a 'impolite' add-on ; that either FireFox added itself , firebug , or noscript. The addon is "AAllDealApp 1.1". . In the mozilla clone called PaleMoon , noscript didn't add that other add-on. .. Here is the bbcode link to the screenshot : [URL=http://www.imagebam.com/image/f31639410742594][IMG]http://thumbnails106.imagebam.com/41075/f31639410742594.jpg/IMG/URL [URL=http://www.imagebam.com/image/881957412270526][IMG]http://thumbnails107.imagebam.com/41228/881957412270526.jpg/IMG/URL ... "Bad add-on" ;(

Positive_X said

It turns out that it was was caused by a 'impolite' add-on ; that either FireFox added itself , firebug , or noscript. The addon is "AAllDealApp 1.1".

I searched, but found no information on this. Do you know where this came from or what it is?

You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.

There are malware that seem to randomize the names of Firefox Add-ons to make them harder to research, but that pattern of extra letters and misspellings is a giveaway if you look on the Add-ons page.

The one in Autoruns is an IE Add-on (BHO), so there seems to be a systemic infection. I suggest:

Open the Windows Control Panel, Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help surface undisclosed bundle items that snuck in with some software you agreed to install. Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it. Take out as much trash as possible here.

The automated cleanup tools suggested earlier probably would also be helpful.