I am an amateur but I found this solution to the hang problem that was
plagueing my system.

In the Award BIOS advance CPU setting I disabled the Intel timing control
and the CIE. I found this suggestion on an overclocking site.

This seems to have cured the hang problem completely and has allowed the
system to sync at a higher speed. Vista would not run well even under the
stock and recommended settings in the BIOS. I had not attended closely to
these settings previously. The same system, the same settings, worked
flawlessly in XP 32 and XP 64. Not in Vista. Your Display module seems very
sensitive to this issue and would freeze when the system lagged, worse at
higher bus settings. Memory diagnostics did not detect the problem.

Just thought I would past that on. The world is good now. No more screen
freeze.
--
Pentium D (2.8ghz)
2 gb Corsair XMS ram 800mhz
ECS PA1MVP mb (ATI x200 crossfire chipset)
(1) ATI 1600pro 512mb pcie video
800 gb sATA storage (total)

OS Boot: Vista buisness x32 / XP pro x64

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