Your son has the Trojan? Oh no! The first case of a computer virus making the leap from computer to living organism! We are teh doomed!
Sorry. Couldn't help making fun.
Please accept my sincere apologies and this link:
There, you will find the solution to the exact same problem that you have. If you have problems with opening the link, then this is the reply to the person whom had the exact same problem as your son.
Delete the file manually and then empty your recycle bin.
Then go to Windows Update and download Service Pack 2 and ALL New Critical Updates. Without these you're wide open to reinfection.
I hope that helps and please accept my sincerest apologies for that awful, awful joke.