Take the following steps and all will be well:
Download AVG Anti-Virus
http://free.grisoft.com/doc/1
Download Spyware Doctor
http://www.pctools.com/spyware-doctor/?ref=google_sd
Download EMule
http://www.emule-project.net/home/perl/general.cgi?l=1
I have been using that set-up for years and have never had a single problem. Spyware Doctor costs a little, but it does an EXCELLENT job, and the choice on there is very large.