If you don't have an anti-virus scanner, here's a great free one:
http://free.grisoft.com/doc/download.../frt/0?prd=aff
And if you can't install it for whatever reason, then try this free online scanner:
http://housecall65.trendmicro.com/
And for spyware, I recommend both of these:
Spybot S&
http://www.safer-networking.org/
Lavasoft Ad-Aware:
http://www.lavasoftusa.com/products/ad_aware_free.php