To check if you have it, you can try the microsoft site,
http://www.microsoft.com/security/incident/sasser.asp
step 3, you can click on the button and the site will detect whether or not you have the sasser virus.
Have you tried the removal tool from the symantec site
http://securityresponse.symantec.com...oval.tool.html
First you need to determine what variant of the sasser virus it is.