Event log errors

I recently checked my event log and theres a huge list of warning, error, and critical events.
Most of them just say

Windows has started up:
Boot Duration : 40922ms
IsDegradation : false
Incident Time (UTC) : ‎2011‎-‎11‎-‎14T01:53:12.656000300Z

or

Windows has shutdown:
Shutdown Duration : 12764ms
IsDegradation : false
Incident Time (UTC) : ‎2011‎-‎11‎-‎14T03:51:07.977101900Z

I have no idea what is going on when my computer shuts down or starts up. Heres some more

The Desktop Window Manager is experiencing heavy resource contention.
Reason : CPU resources are over-utilized.
Diagnosis : A sharp degradation in Desktop Window Manager responsiveness was observed.

The Desktop Window Manager is experiencing heavy resource contention.
Scenario : The Desktop Window Manager responsiveness has degraded.

This one right here was critical

Background optimizations (prefetching) took longer to complete, resulting in a performance degradation in the system start up process:
Name : BackgroundPrefetchTime
Total Time : 40103ms
Degradation Time : 11711ms
Incident Time (UTC) : ‎2011‎-‎11‎-‎14T21:41:47.734000400Z

All that was just in one day and there was more. I have also been having a problem with playing games, my pc randomly restarts its self when playing mw3 or skyrim. I debunked RAM as being the problem but more of the power supply being crap. Help would be MUCH appreciated! Heres my rig

Amd Phenom II 955
MSI hd 6850
Corsair CX500 powersupply
Asus sabertooth 990FX motherboard
1TB HD
CD/DVD reader
4GB (2GBx2) DDR3 1333 PC-10600 G.Skill RAM
5 fans