a friend of mine was having a very similar problem...his daughter reckoned she was only using it for messenger...no one else at the house used the pc...yet it ran like a pig and had constant popups.
they had an up to date norton 2005 Av/firewall, MS antispyware/malicious software removal tool, adaware and spybot... but nowt could get rid of the rubbish on the pc (specificaly aurora and abetterinternet cr*p)
i came across the info below and went through it on that pc and it found ...and more importantly, removed a hell of a lot of trojans, virii, adware and spyware.
the pc is now running like a dream
here's where i found the info and is the 2nd thread titled 'abetterinternet uninstall tool, and is the post by pcbutts1
http://www.microsoft.com/technet/com...xp=&sloc=en-us