the ONE system you should know everything about, and the one system where you can be absolutely sure. Having to jump through hoops to run applications doesn't make it more secure. It makes it more tedious. At the server level, there's no reason why users should have access to more than is doled out by the administrator, but on the desktop (not counting domains, where the desktop is a homogenous experience), you're the administrator, and you're just as likely going to get rooted if you have administrator access to start with as if you had to click an extra button. The difference is that the latter is going to get old fast. Actually, I run my personnal computer with the lowest amount of rights required (User) and I don't find it annoying. It just add some more steps to install a software (run as), but I'm not a software-junkie so it doesn't happen frequently. So, given that I didn't do anything differently when I ran Steam successfully in the end and that there was no confirmation dialogue, I'd think that either: the service component wasn't installed but for some reason Steam decided to let me through anyways (weird... why..?) somebody compromised my system and disabled UAC at the moment I was trying to run Steam. How can I check that the component is installed and how can I install it if it isn't? Easiest thing, hit the windows key, type "msconfig" without the quotes, hit enter, click through the UAC