Norton found a trojan horse and can't fix

I click on Trojain horse
it send me here
http://securityresponse.symantec.com/av ... horse.html

Before I do anything ASk Brain Trust Here before something Stupid again.
Should do this at all it a C:\winnt\system32\mpegcore.dll

I hit the same thing a couple of times recently. Did norton catch this before it started? I didn't see anything when I did a complete virus scan.

Reboot in safe mode (press F8 while booting) and delete mpegcore.dll. Not really a system file. Make sure your system restore is turned off or it may comeback.