AFAIK any windows PC can get malware. Other OS's less so, perhaps because they don't use activeX, but that's a religous arguement for another place and time. I would suggest running spybot and ad-aware in safe mode after updating their definitions. And I've heard ( haven't seen yet ) that some malware will install in that single user's context only, so you would have to log in and run the antispyware apps as each user... perhaps.