First, do you have reason to suspect a virus? A mouse pointer jumping around is typically caused by dusk and gunk on the ball rollers inside the mouse. Turn it over, rotate the plate around the ball and drop it out. Look closely at the three rollers that the ball activates...are they gunked up or clogged with debris? Blow them out and make sure they're clean and put the ball back in.
Good hunting.
Trey
Oh yeah, Google "Security Tango" and follow the first link.
Mouse jumping all over the plae it typical of 'dirty mouse ball/roller'. Hey and we all know there is nothing worse than dirty mouse balls..ahahahhaa..seriously check the mouse ball and the rollers. they gather all kinds of junk. If its a laser mouse make sure you on a decent surface and not just placing the mouse on the desk. Maybe its sensing some dirt or irregularities on the desktop.
If you still suspect virus/trojan, you might want to check out Hijack this and see what programs are taking you to places that you need not be. If you dont know what the programs mentioned in each line are goole them to see if they are spyware/trojan stuff. I love Malware Bytes. Great program to clean your system and then run the free AVG.
Make sure you install and then run the updates on each program. then go to safe mode and do the scans.
Art