Click on the link below and follow the steps to remove the add-ons from all your browsers, then run a few scans for adware, spyware, and other malware.. Such is frequently the cause of browser issues such as yours. In addition, try Googling "reset Firefox", etc.
http://forums.cnet.com/7726-6122_102-5509131.html?tag=posts;msg5518840
Hope this helps.
Grif
I have an HP pc running Windows Vista, Pentium 4 HT. I get this frequently using Google Chrome and Firefox.

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