Hi Guys,
Thanks for your replies! I think that the latest driver for my video card nvdia 9400 GT caused the problem.
I returned to Vista Ultimate

and at first my pc worked correctly.... so i updated my driver.
Frankly i have had enough of it and wanted to watch a movie, so i shut down my pc, connected it to my tv (hdmi) and started it.
But.... the damn thing failed to start
The only difference this time was that when i started it again it high lighted START WINDOWS NORMALLY so i did.....
And it started

but.... after watching 2 movies it froze again!!
I am going to download the latest build of Windows 7 right now because Vista is really .....