After password, only grey geometric forms

I can only get Vista (64-bit) to display a desktop in Safe Mode.

If I try any of the other modes, inlcuding the VGA one, after I enter my
password there is a comment about creating my desktop, then a screen with
only very, very faint geometric shapes (mostly triangles) in shades of grey
appears.

The only thing I can do at that point is <ctrl+alt+del> to be able to click
on the button in the lower right of the screen to reboot.

In Safe Mode, everything looks fine in Device Manager -- I tried finding new
drivers for display adapter and monitor, but reply is that I have the most
current. I do get a glimpse of the desktop wallpaper after I select the
reboot option.

My system passed the Vista Upgrade Advisor: ASUS P5LD2 mobo, Intel 930 (3.0
ghz dual-core) processor, 2GB DDR2-533 RAM, ASUS ATI 1300x vid card.

I re-installed Vista a second time, and same thing.

What do I try next???