I installed 3 identical HP PC's with Windows 7 Pro in a business. There are only a few programs installed, the same ones on all PC's there. One of the new machines will not reboot or shut down completely after logon unless the power button is depressed. It will function normally if you shut down or reboot before logging in. There is no domain, just a peer-to-peer network on the same workgroup. I installed default settings in BIOS. I checked for corrupt drivers. Keyboard & mouse are PS2. Monitor uses on board VGA. Nothing else is plugged in besides the LAN. Results are the same for std or admin users.