To ensure that you manage the removal of any crud from your PC do not boot up
in 'normal' mode. To do so, allows all 'start-up' applications and
utilities, plus all drivers etc to be loaded: INCLUDING the little pieces of
crud.
Start your PC in SAFE MODE and make sure that your modem is disconnected
from the PC - especially the cable modem and DSL modem types.
Run Spybot Search and Destry and/or any other crud killing application that
you have. This gives it the best chance of working prperly.
Then restart your PC in SAFE MODE again: repeat the 'cleaning' cycle. Run
anti-spyware and anti-virus applications.
Reboot your PC and this time, keep the modem disconnected. Test that all
applications are working properly and that you don't have any unauthorised
attempts to connect to the internet. The crud, if not entirely removed, may
cause your browser to launch or your internet connection to be connected in
order to go and do it's nasty work. If you do not have the modem connected
it can't reininfect.
Provide that all works as one would want, it can be considered appropriate
to reconnect the modem.