I have had this problem on my Alienware system.
Some pc OEM's install junk and the system is heavily fragmented. If you
tweaked your registry or performed multiple installs/uninstalls this can
cause corruption.

Try going to event viewer following a lockup (make sure to make note of
the time of lockup).
For me I did 3 things that fixed the problem-

1. do a full defrag through command prompt
startaccessoriesright click command promptrun as administrator
type: "defrag c: -w" (without quotations)

2. If problem still occurs check system for malware, and/or restore to
a date before issue of lockup occured.
'Antivirus scanners'
(http://www.vistax64.com/system-secur...-scanners.html)

3. If all else fails then backup files, and perform a system repair as
issue may be caused by corruption of o/s. In my case I did a complete
reformat and reinstall and the problem was gone. My freeze ups were a
result of either registry corruption or file corruption. I prefer
reinstalls as opposed to repairs, but you may want to do that as a last
resort. Also perform a complete pc backup if you choose to reinstall. It
will save you hours of time if you ever need to restore again.


--
rive0108

Alienware Area-51 M5790
Vista Ultimate x64 sp1
T7600G Core2 Duo 2.33 Ghz (overclocked to 2.66 GHZ)
ATI Mobility Radeon x1900 256 MB
1920x1200 WUXGA
4GB DDR2 PC5300
HP digital Tuner express card
200 GB 7200 RPM HDD RAID 0