How do I remove trojanwin32 from my computer?

Q: I apparently have a problem with trojanwin32 — presenting as http://b.admedia.com/banner.php? (and it goes on for many lines). Am now operating in safe mode but only mozilla seems to be able to connect. Have Windows XP – home, I believe. When searching the b.admedia popup online, the info I found said it was trojanwin32.

I opened safe mode with networking but my microsoft security essentials cannot connect to update. I ran updates yesterday, but the info I found said the virus can prevent updates. Anyway, yesterday I ran MSE, spybot and malwarebytes. Spybot found one issue, but it’s one that shows up periodically – can’t remember the name (Right Media maybe?). Would appreciate help!