Go to Download.com and get yerseff a copy of 
Spyware Search & Destroy and also get a copy of 
Ad-Aware or some similar program.  They're both 
free.

Run them both regularly.

AND set this site for maximum security, or 
whatever level you need to make it work properly.

I haven't had any problems at all with this site 
since doing all of the above.  Doesn't make it a 
good thing that we have a spyware problem, but 
you can at least take measures to deal with it.