Firefox suddenly will not open

Question

I have an Acer laptop with Windows 7 Home Premium 64 bit. Firefox will no longer start when it used to work perfectly on this system. None of its files are listed as still running in Task Manager. I read a suggestion to go into firefox.exe –ProfileManager to create a new profile, but all I get is a box with a black bar and a red X to close it out. I've used system restore a couple of times, and went back to before the last 2 windows updates. That helped a little with some other problems, but Firefox still won't open. I also used PowerSuite's Registry booster, but still no help getting Firefox to open.
Any help is appreciated. If I need to change a registry key, please provide exact detailed instructions. Thanks in advance.

Answer 1

This crash is due to malware. Please see the below to fix this.
Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.
You can try these free programs to scan for malware, which work with your existing antivirus software:
* [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner]
* [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware]
* [http://support.kaspersky.com/faq/?qid=208283363 TDSSKiller - AntiRootkit Utility]
[http://windows.microsoft.com/MSE Microsoft Security Essentials] is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.
Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article.
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