It is always a good idea if scanning for virus's to turn off system restore. also be aware norton has a lot of probs with false readings. For example it removes a file in TS as a virus but it isnt.
If possible do an online scan as well as norton and NEVER totally rely on 1 AV prog
Useful links bit:
http://www.spywareguide.com/txt_onlinescan.html
http://vil.nai.com/vil/stinger/
http://www.f-secure.com/virus-info/