Question : Problem: Computer Fails to Restart. Must start with on/off button.

The computer seems to be running fine but will not execute the restart command. When you click OK to restart the PC turns off completely and requires pushing the on/off button to restart.

Answer : Problem: Computer Fails to Restart. Must start with on/off button.

Not like this is a common occurrence :p

Seriously though, because the problem could be rooted in several places, can you provide some more info, e.g.
- do you mess around with BIOS settings?
- does Windows cleanly end before shutting down?

Maybe try a "repair install" of Windows and check to see if there is something wrong in the BIOS setup.