Reboot your machine.
Download and run cCleaner.
try completely wiping it off your computer and re-installing it. That should work!
Try rebooting your computer. Firefox should also work again.
start using opera
I use Opera and recommend it. However I keep Firefox as well for those few badly written sites that will not work with Opera.
Don't delete Firefox if you want to retain you settings and bookmarks until you have exported them. Then do a new download and install the latest version of Firefox 3. and import your saved details. You may find it is worth running a Registry Cleaner, then re-booting, between uninstalling the old FF and doing the reinstall.
It may also pay to install Opera first as it will import from Firefox and save your settings for you and you thus have two saved sets of information in case something goes wrong.
The suggestion of checking for a virus or spyware is valid too. Installing Real Player installed several spyware items and corrupted Firefox for me about a year ago, and it did require changeing to Opera, then uninstalling FF, then doing a Registry Clean and full spyware clean after I got rid of Real Player.
well ! sometimes these symptoms indicate the presence of some malicious programmes like spywares, or viruses, which can make your browser close or open suddenly and unexpectedly and even open some sites on their own. You could probably run a virus or a spyware scan preferably.
You don't have to uninstall to reinstall. You are probably experiencing a faulty .dll file somewhere. Browsers are prone to this problem. The solution is to find a mirror site for your download. Installing from a different site at a different geographical location should give your computer and the host server better communication, and the .dll files will all come thru ok. Just install the new files into the same directory so it will refresh the corrupt data. Good luck!