Windows 7 Freezing and blank / strips on screen.

Hello all.

I have just installed Windows 7 for the third time. And each time I have had the same problem. It runs along fine then suddenly I'll get a blank white screen and the system seem's to have frozen. It can also be blue and white stripes or white with grey lines.

Is this a known bug and what is the cause of it?

My computer meet's minimum specifications.

The first time I installed it and got the problem I thought it could of been because it was a funny install. It made a Windows.old and I thought this might be messing with it. The second time I installed it I upgraded over the previous install, Just to make sure nothing was missing. This third install I have done on a separate partition. So that it shouldn't matter what is on the others.

But I still get the same problem.. Is this possibly an error in the install file I got? I did have a problem at the end of the download and had to re-open the download page. Problem?

Thank's Rich.

-----Edit-------

Okay I just restarted after the white screen, and now it's in a windows 98 look-a-like skin. And I cannot access anything.

Explorer.EXE
Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item.

That was clicking on 'Computer' in the start menu.

Thank's Rich.