you can try out a free online virus scanner here
http://housecall.trendmicro.com/
for a free antivirus, a lot of people like avg antivirus
http://www.grisoft.com/us/us_dwnl_free.php
other things to do is run a spyware/adware scan.
Once you have all of that checked out, then you might want to run a chkdisk(scandisk) to check for file corruption. Since you have systemworks you can do this through disk doctor ad if there are any errors it will probably have you reboot for it to run (not sure, the 2002 version i use does this for win 2k).