trojan.gen.x not found by Norton?

Hi!

 

I keep my security suite updated and run scans religiously.  Never an alert.  However, when I took the computer into best buy for a hardware upgrade they informed me that the computer had a trojan called:

 

trojan.gen.x

 

I immediately went home and updated Norton and ran a full scan.  Still, no issues reported.   Before I spend the $130 best buy is requesting for the removal, I thought I'd check here to see if this is a valid trojan and if so why doesnt the Security Suite pick it up?  Can it be found and removed by Security Suite?

 

Thank you.

 

Kev