Mysterious Problem with random system hangs

Hello,

I am stumped! Installed Vista with no problems. Set up the dual boot with no
problems. Still, I really cannot use it (vista) because it randomly freezes.
At first this resulted in an approximately 30 second freeze from five to 30
minutes into a session, but now it occurs more frequently and the system
needs to be rebooted each time.

XP 32 was stabile on this machine and XP x64 runs very well on the same
system with no problems, so I think this is a Vista issue.

Now, when I look at the "system reliability report" (nice feature by the
way) all I see is an occasional call-out for "service failure" near the time
of the hang. However I am not sure which this might be or why it would cause
a hang, and it does not indicate this every time. Other than that all the
diagnostics check out fine.

As far as I know I have all the current drivers. Memory usage seems to be
running at about 30%.

Could this be an ATI chipset problem? It is a relatively old MB.


--
Pentium D (2.8ghz) @ 3.0ghz
2 gb 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