I want to inform the readers that I finally found the solution, suggested by specialists at the Kaspersky forums.

The problem was the replacement of all google adsense ads by affiliate ads from another network. Thus, EVERY site using google adsense that I visited, would have their ads replaced by ads from another network. I bet 99% of the people infected by this don't realize it. But it can be a substential loss for webmasters with adsense on their site if people don't see their ads.

Anyway, something (probably a spyware/ malware, didn't find the real culprit) modified my windows host file, located in /windows/system32/drivers/etc/host and added those lines:

66.98.xx.xx auto.search.msn.com
66.98.xx.xx auto.search.msn.es
66.98.xx.xx pagead2.googlesyndication.com

Only after deletion of these lines from the file, + clearing browser cache and cookies, was I able to see the proper google adsense ads again.

This is a very vicious problem, since even after clearing my computer from all potential spyware, the problem was still there since the file still had those lines.

Google adsense team didn't had a clue about my problem, and didn't care much. Still, I feel it can be a serious problem for webmasters.

Cordially,
Brakkar

[edited by: jatar_k at 7:53 pm (utc) on July 27, 2006]
[edit reason]
[1][edit reason] no specific ips thanks [/edit] [/edit][/1]