Oh dear just come across the same nastie on a friends computer and found this
http://elamb.blogharbor.com/hacked/removesmithfraud.htm
it looks long and complex best tried when sober me thinks.
good luck
Rickity
ps spy bot picks it up but does not get rid of it
Edited to say 6 hours of following the above instructions later, reinstalled xp from scratch, that got rid of the blighter