Did this just start or have you changed or added anything?
You can disable these features through the setup (power settings), through control panel, device manager (power options), and other ways. Look in those places first.
Past that go into safe mode, see if you can power down from there.
I have a pentium 4, 256 MB Ram, Windows XP, Hewlett Packard PC. When I go to restart the computer either through the task manager, the start menu, the shutdown, or ctrl+alt+delete, the PC will not reboot. I have to press the off button to reboot it.
What is the problem, and how can I fix it? Thanks