Virus Scan, Malware scan, reset you browser to defaults, dump your internet cache and your cookies. those are the things I do, usually in that order. additional stuff to keep yer winderz box happy is run a scandisk and then defrag.
alternative to that is use a different browser (firefox, opera, what ever mac uses, nautelus)
on some setups it (Opera) works great... 'cept I don't have the nifty little powers that I have with ff... I can't get it to work worth a crap with my current( and very absolete) set up
I've never seen it one a windoze box before though