few days ago I both Dell Inspiron N7010 and I have WON'T-RESTART problem.

When ever system restart is needed my laptop just won't do it. This problem occurs while installing windows (XP, Win7-32, Win7-64), also when I click RESTART from Windows, also when System diagnostic (F-12 on boot -> Diagnostic) finish.

F12->Diagnostic does not report any problem (with full memory test)

System began restart process and then just stuck ... then I must click power button to turn computer off, and then to turn in on again?

I think this is some hardware problem? Does someone have some ideas ?

I have latest BIOS installed, dual core Intel, 4GB RAM.