"3.3V out of threshold" Is my power supply dying?

how do you tell if your power supply is dying or not? My system crashes now all of a sudden. This seems to happen when I play battlefield1942. But only just recently-like today. Could it be that i need to reformat as my system is unstable from all the programs installed/uninstalled, adware cleaning, win updates, etc. The latest program I installed was Maya4.5 but I uninstalled this thinking this might be the cause. Also ran spybot, ad-aware, spywareblaster, cwshredder, crapcleaner, online virus scans hoping that it was in here that the problems were occurring. Haven't tried playing BF1942 again until i get some suggestions from the forums on what to do first.

My sys is an amd64 3500+, asus A8v deluxe mobo, 1g ram, x800 pro vid card, win xp with sp 1, power supply is a Thermaltake purepower W0009R:TT-420AD 420W, dvd burner. My Cpu temp is about mid 40s to mid 50s under load.

The Asus prob says 3.3V out of threshold. What does that mean? Not enough power is being supplied to the computer? Do i want my voltage to be closer or lower than the 3.3V? It sometimes goes to 2.832v according to the asus prob.

The error code i get:
BCCode : 9c BCP1 : 00000004 BCP2 : 80543070 BCP3 : B2000010
BCP4 : 00010C0F OSVer : 5_1_2600 SP : 1_0 Product : 256_1


C:\WINDOWS\Minidump\Mini021905-01.dmp
C:\DOCUME~1\York\LOCALS~1\Temp\WER1.tmp.dir00\sysdata.xml

Any ideas to what is occuring? Or to point me in the general direction for answers. Again should i reformat and see what happens?