Screen on my notebook goes blank

[El Camino]

I have a Toshiba Satellite 5105-S607 notebook. Every once in a while, when I am restarting my notebook, my screen goes blank (doesn't turn on). I have to shut it down and than turn it on again. Than everything turns on as normal without any problems.

Does anybody have any idea why does this happen?

By the way notebook has 512 MB RAM and 40 gigs HD. I have WinXP Pro on it. It has NVIDIA video card.

[septimus]

Could it be that a power saving feature is kicking in? If you disable all power saving functions in the BIOS maybe that will no longer happen.