Firefox instant-crashing all the time

Since you say you already scanned with the various tools and they came up clean, I am moving your thread to the software forum.

Perhaps uninstalling FF might help:

We are going to be uninstalling your old version of FireFox and installing the new version. So do the below to save bookmarks:

• Run FireFox and click Bookmarks.
• Then select Organize Bootmarks.
• Then on the next window click File and then select Export. Save the bookmarks.html file to your Desktop for later use in importing.

Now download and save the installer for the current version of FireFox but DO NOT install it yet. Get it here: Mozilla FireFox

You will need to exit FireFox now and use Internet Explorer to continue with the below until we reinstall FireFox.

Start by uninstalling FireFox and then reboot. Do not skip the reboot.
After reboot, delete the below folders:

C:\Documents and Settings\UserAccount\Local Settings\Application Data\Mozilla
C:\Program Files\Mozilla Firefox

where UserAccount is the actual user account name being used.

Now reinstall FireFox from the file previously downloaded.
Import your bookmarks file. (similar process to exporting).


Is FireFox working okay now?

 

That doesn't sound good. Ok. Maybe you are having malware issues. Instead of moving you back to the malware forum, I would like you to do this:

READ & RUN ME FIRST. Malware Removal Guide

Then start a new thread in the malware forum and attach the requested logs. We need:
SAS
MBAM
RootRepeal -- if it runs
ComboFix
C:\MGLogs.zip --- from running the C:\MGTools.exe

Depending on what we find, we may send you back to this thread.