Vista - Fixing lockup/freezeups in Vista

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
start>accessories>right click command prompt>run 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

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.