This is definitely caused by a spyware. If it came from your own computer, whatever programmed found it would identify itself (like AVG Anti-Virus or something like that).
I think I've found a procedure to remove it at
http://forums.techguy.org/security/452667-solved-spyware-quake.html , and the post by itself is at
http://forums.techguy.org/3464303-post4.html. You should try that and then tell us about it. Also, it would be good to know which browser you're using (Internet Explorer is like a giant backdoor for viruses and spywares) as well as any anti-spyware software you have. I recommend Spybot Search & Destroy, Lavasoft Ad-Aware and SpywareBlaster (all free).
---
"With the first link, the chain is forged. The first speech censored, the first thought forbidden, the first freedom denied, chains us all irrevocably." [...] The first time any man's freedom is trodden on, we're all damaged. - Captain Jean-Luc Picard
B*tch, meet reality. Reality, meet b*tch. - Me