Major problem and it won't repair! (Trojan.Brisv.A!inf)

Arghhh.  I'm so upset.  My old computer died...DIED because of LIMEWIRE.  I no more than got the new computer installed and set up, and unbeknonst to me, my teenage daughter downloaded LIMEWIRE!  Well, wouldn't you know it?  Guess what.  I have a TROJAN.  I did all the things I was instructed to do.  I installed and ran the removal tool for Trojan.Brisv.A!inf.  I did exactly as the instructions said.  After it ran, it said no infection was discovered.  I did an update and ran another scan.  Well, here it is again.  It says I'm infected with this Trojan.Brisv.A!inf.  WHY?!?  I did everything as instructed.  It is as if the tool didn't do its job.  Any other ideas?  Now what do I do?  I have the removal tool still sitting on my desktop.  Should I try it again?  Should I remove it?  I completely removed LIMEWIRE and had a discussion with my daughter about NEVER INSTALLING THAT CRAP AGAIN.

 

In the meanwhile, is my computer screwed?  What exactly will this infection do if I cannot remove it?  What are the risks?

 

Please respond.  I could just cry thinking that my new computer is infected and I can't remove the infection even after doing what Norton says I should do.

 

Cindy :( :( :(