Windows 7: IE and Firefox stopped working

I had my PC running over night and when I checked it in the morning, I found neither IE nor FF were running (maybe I closed FF, that's not important). So I tried to launch them, but neither browser started and FF threw the following error: "XULRunner - Couldn't read application.ini".
I cleaned Windows up and restarted, but it didn't help. I found both apps can run when admin rights are used.

Where the problem can lie? Should I try changing some registry values?

It sounds like you may have a corrupted user profile. Try creating a new user and running them from there. Post back if you have any issues with a new user.

Create a new user:

User Account - Create

I'll look at it deeper tomorrow. I should also mention, that Opera, Chrome and even IE x32 all work fine.

Surprisingly it's OK now. I should have just restarted after cleanup once again.

Ah, okay. Glad to see it solved.

That's so weird, it's not working again. I hope I'll solve what the cause is.

Have you tried a new user profile yet? If not, try to see if the problem comes back with a different profile.

I forgot to reply. In the end it looks like the problem was caused by lack of free space on HDD. After deleting some files and defragmenting everything works again.

Thank you for posting back your solution. Even though you were not getting a blue screen, the http://www.sevenforums.com/crashes-d...tructions.html would have helped us determine the space issue.

Just thought I'd throw that out there for future reference. Glad to see it solved.