Hi,

It looks like there could be more than one reason that could trigger this including Windows OS malware. The Windows OS forum would be helpful. If you suspect malware, these forums would also be helpful:

http://www.bleepingcomputer.com/forums/forum79.html

http://www.spywarewarrior.com/index.php

http://www.spywareinfoforum.com/

http://www.wilderssecurity.com/

Which Firefox version are you using?

Try a clean (re)install and delete the Firefox program folder (C:\Program Files\Mozilla Firefox\).

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 13.0.x: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

thank you my friends but im remove all of the folders * remove the firefox and after uninstall im delete the folder in the c:/program files (86)/mozilla ( im just deleted not shift delete ) and im take a backup of profile folder of firefox and im download the last version of firefox 13 and im trying to install it but its not working also!!!!

Then most probably the problem could be a general Windows error. The Windows OS forum would be helpful in this regard.

ooh my G#D !!! Norton is Best ! thank all you guys ! ;) im install norton anti virus and my fire fox is workin after scan!!! :))) huuuuurrrrrrraaaaaaaaaaaaaaa

I got this problem since yesterday. I can't open firefox or IE. Ive tried the DEP trick with the file regsvr32.exe but that doesnt solve it. Ive tried reinstalling firefox. Didnt help. Ive tried to run in administrator mode. Didnt help. Tried to replace regsvr32 from another windows 7 computer, but same window comes saying Microsoft register server has stopped working. Here's the event log details:

- System

 - Provider 

  [ Name]  Application Error 

 - EventID 1000 

  [ Qualifiers]  0 

  Level 2 

  Task 100 

  Keywords 0x80000000000000 

 - TimeCreated 

  [ SystemTime]  2012-07-11T20:27:21.000000000Z 

  EventRecordID 53856 

  Channel Application 

  Computer RossaEVGA-PC 

  Security 

- EventData

  regsvr32.exe 
  6.1.7600.16385 
  4a5bca28 
  MSVCR100.dll 
  10.0.40219.325 
  4df2be1e 
  c0000417 
  0008af3e 
  e7c 
  01cd5fa3920bd224 
  C:\Windows\SysWOW64\regsvr32.exe 
  C:\Windows\system32\MSVCR100.dll 
  d0953b59-cb96-11e1-b257-001fbc02549e

If I click to open firefox I get a small window 1 millisec before the actual error window and if Im really fast I can manage to open firefox in safemode. Thats what I did for this session. Im hoping for help or tips.

Update: I fixed my problem by scanning in safemode with Malwarebytes;

Files Detected: 4 C:\ProgramData\Windows\msseedir.dll (Trojan.FakeMS) -> Quarantined and deleted successfully. C:\ProgramData\Windows\ccdxmmde.dat (Malware.Trace) -> Quarantined and deleted successfully. C:\ProgramData\Windows\drss.dat (Malware.Trace) -> Quarantined and deleted successfully. C:\ProgramData\Windows\xessmsxe.dat (Malware.Trace) -> Quarantined and deleted successfully.

This made Firefox work normally again.