I'm almost finished bringing my colleague's PC back to life. After those first 209 objects that Ad-Aware detected, the 40 entries in spybot SD, and the 19 virus/trojan horses, I updated detection rules and found another 42 spyware entries (and fixed them) scanned the machine one last time to catch 2 more trojan download files.
Patched it with 54 critical and important hotfixes, rebooted and installed another 22 optional patches. SP1 is out of the question since it seems the SN is blocked... maybe a key generator could be a solution to make sure the box is more secure?
In the mean time, my trusty MS Explorer IntelliMouse - which has served me well over the past 3 years - seems to be running into trouble more and more. It very frequently loses its USB connection, and then takes a few seconds to be detected again, or even requries a manual re-connect to enable it again. I think I'll have to get myself a new one, don't I?