1. Why are you still using that old 3.0.5 version? It is lacking 100's of security fixes that the latest 3.6.13 version of Firefox has.

2. Sounds like you picked a dose of Malware.

Install, update, and run these programs in this order. They are all free for personal use, but some have limited functionality in the "free mode" - but those are features you really don't need to find and remove the problem that you have.
(Not all programs detect the same Malware.)

Malwarebytes' Anti-Malware - http://www.malwarebytes.org/mbam.php
SuperAntispyware - http://www.superantispyware.com/
AdAware - http://www.lavasoftusa.com/software/adaware/
Spybot Search & Destroy - http://www.safer-networking.org/en/index.html

If these don't find it or can't clear it, post in one of these forums for specialized malware removal help:
http://www.spywarewarrior.com/index.php
http://forum.aumha.org/
http://www.spywareinfoforum.com/
http://bleepingcomputer.com

Thanks, I upgraded to 3,6.13. I already had three of the four virus fighters and ran them. The culprit still pops up.The malewarebytes did find and clean up 22 bad ones. The superantispyware and the spybot found it AOK.. I'll work on it again later After about four hours of this all I need for one day

I, too, have been having this issue and have done most of the above mentioned. I'm not only getting the Best Buy and fast food one but also a new one started up tonight about unemployment.

What's strange is that I didn't have these problems until after I installed the latest version of FireFox.

These things are driving me nuts and I don't want to have to take my computer in to be serviced!