Firefox 3.6.10 crashes when I open it, even after uninstalling, deleting the default profile and all user appdata folders.

Question

Firefox was working fine, but recently it's just stopped working. It instantly comes up with the error message 'Firefox Has Stopped Working'. I have pasted the error message below
Problem signature:
Problem Event Name: BEX
Application Name: firefox.exe
Application Version: 1.9.2.3909
Application Timestamp: 4c8fdcc5
Fault Module Name: StackHash_8228
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Offset: 8a101e70
Exception Code: c0000005
Exception Data: 00000008
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 2057
Additional Information 1: 8228
Additional Information 2: 8228e43d426cfb63ad023de96d440ede
Additional Information 3: 1853
Additional Information 4: 1853d009ebe0b1df5f24e024bd05eb79
I really have no idea why this is happening. I have a feeling it may be some sort of virus or malware but i've done scans and nothing has come up. Internet Explorer is working fine. I'm on Windows 7.

Answer 1

This can happen if adware  Genieo is installed without your knowledge. Removing it will help,
1. Download and use free AdwareMedic to remove the adware
    http://www.adwaremedic.com/index.php
    Install , open,  and run it by clicking “Scan for Adware” button   to remove adware.
    Once done, quit AdwareMedic.
               or
    Remove the adware  manually  by following the “HowTo” from Apple.
    http://support.apple.com/en-us/HT203987
2. Safari > Preferences > Extensions
     Turn those off and relaunch Safari to test .
     Turn those on one by one and test.
Note:
  If you don’t have another browser installed,
startup into SafeMode, log into your account
and download  AdwareMedic or the removal instructions from Apple.
Follow these steps to start up into Safe Mode.
Be sure your Mac is shut down.
Press the power button.
Immediately after you hear the startup sound, press and hold the Shift key. The Shift key should be pressed as soon as possible after startup, but not before the startup sound.
Release the Shift key when you see the Apple logo appear on the screen.
After the Apple logo appears, it may take longer than usual to reach the login screen. This is because your computer is performing a directory check as part of Safe Mode.
To leave Safe Mode, restart your computer without pressing any keys during startup.
Source:    http://support.apple.com/en-us/HT203987