The other day I grabbed the latest RTM of Windows Server 2008 to try out in Virtual PC The installation process went smoothly and without incident, but once I got logged into the machine the processor of my host OS was spiking at 100% any time I would click anything in the 2008 VM. I figured installing the VM additions would resolve this, but no luck. I double-checked my power settings on the host OS and everything looked in order so I was stumped. So when I finally fired up task manager in the 2008 machine I found the culprit: TrustedInstaller.exe was consuming 80-90% of the guest OS CPU. After some investigating, apparently this process manages software updates within Vista/Server 2008 platforms. Since I'm only planning on running this as a test OS I just went ahead an killed the process. I don't need no stinking updates! We'll see if this adversely affects anything else, but at least I can now run the VM at a reasonable speed.