Quote Originally Posted by Borgod View Post
I'm having extreme difficulties installing Vista using the 4 DIMM slots. It just crashes with blue screens.

I had this problem when installing with 2 sticks, but that was because I was using 2T in the orang slots.

XP works perfect, and all Memory Diagnostics and memtest testing comes up with no errors.

Bizarre.
There is a known bug with Installing Vista with more than 3GB of RAM... http://support.microsoft.com/kb/929777

Try removing some RAM, installing Vista, applying the patch, and then reinstalling the rest of your RAM.