Well, I'll give a few more details. It is actually a friend's computer, which initially had Forefront Client Security from Microsoft. I removed that and tried to install a trial version of ESET, which did not install. He had Malwarebytes from before and I ran a scan in Safe-mode. It detected 4 items, which I made it remove. The actual problem is that I cannot open the main items in the control panel. I can still uninstall program from the button in My Computer, but cannot open the Action Center, Network and Sharing Center...you get the tone. The Security service is stopped and my explorer.exe restarts everytime I try to start it. And there is a suspicious 'Windows Update' icon in the notification tray, which disappears as soon as I hover my mouse over it. I was suggested to run a scan using http://www.freedrweb.com/cureit/?lng=en, which yielded 4 results. I removed all of them, but the problem persists. Please help me. I'm a student and about 30-40 of us have this problem.