Issue Loading websites with firefox

Hello, I have windows XP Sp2 and i got this weird issue that some websites like (gmail, hotmail, amazon, ect) dont load with firefox, and this happened after i got the firefox 3. With explorer works fine, on safe mode works too. I tried the system restore but i just got the last know good configuration when i came back it worked but just for one time becuase when i restarted the nb, the same problem again. I disabled the cookies and it moves further, i was able to get to the logging screen on gmail but after that i could not continue because the website request for the cookies to be enabled.
I´ve been reading a lot on the forums and stuff, and i tried a lot of steps; i got rid of Kaspersky because a read it got some problems with firefox, i ran Spyboot search and destroy, ad ware, the microsoft removal tool, vundofix; all was eliminated. I also remove my profile on firefox and create a new one. I remove the firefox 3 a install the 2 version and still the same frinking problem, I read one post http://forums.mozillazine.org/... on a fourm i tried that and did not work, i flush the dns, ping the websites on cmd thay were good, I done a lot and i know ist not all but im out of ideas and i dont want to reinstall the OS again because i got a feeling that even after that i still gonna have the issue,

Any help would be apreciated
Thanks