Scan your computer for malware and viruses etc, and see if there's any addons in FF that's causing a conflict. Are you using Google through www.google.com or the search engine provided with FF? Try both - if they're both stuffed, and there's no conflicts, try another browser like IE (or even Windows Explorer if you have nothing else) and see if you get the same thing.
If other browsers work and it's just FF that's stuffed, maybe uninstall and reinstall the browser - it's small enough. Before reinstall, do a registry cleanout (I use CCleaner (www.ccleaner.com) for quick fixes and System Mechanic 6 for more in-depth stuff.
System Mechanic - not many people know this, but they recently went from version 6 to version 7. Personally, I prefer 6 and found a FREE LEGAL download of it. It's a fantastic product and includes a disk checker, defragger, spyware remover, registry cleaner, temp and junk files cleaner, internet optimiser and a lot of stuff that really helps.
Free, free, free. I'm always searching for the best free stuff. Might as well tell you where to get it:
For some reason, I couldn't use Firefox and had to use internet explorer. Go to: http://www.iolo.com/...u/sm6promo.aspx
and follow the links to register. They will e-mail you your registration information. Download the prog, install, register and it's up and running.
You'll be surprised by how many errors it finds. Most of my errors are cleared out with System Mechanic, although my internet issue at present is a headache. I highly recommend System Mech for XP users.