Just what it says.. How can you tell if your psu isnt strong enough to run your system properly?

Ive been doing some light overclocking and general tinkering around recently and have run into some problems, namely, not being able to oc hardly at all and keep my system stable and functioning on any real reliable level. My equipment is all pretty new, and good solid stuff, it doesnt make much sense that boosting the fsb from 133 to 140 is impossible for my system to handle. I've also had some problems with my cd-rom drive. I can hardly install anything. Somewhere in the middle it just up and says things along the lines of "Unexpected Error - Application Exiting" or "Suchandsuch file has bad CRC - Application Aborting Installation" and other similar errors. I tried installing an extra cd-rom i pulled from an old crappy box I run on the side and installed it.. With that cdrom, one I know works 100% fine, the errors came even faster. Almost immediatly, and on two occasions the computer just turned itself off suddenly when I had a few applications running and load on the system was high.

I'm assuming my psu just cant handle it, but Id like some opinions from folks before I rush out and buy a new one. I dont have much money and anything I can do to save myself some is a big help.

System -

MSI kt4v mobo
AthlonXP 2000+ @ 1.6 (about 37c idle with vcool, 43 w.o, 48-50c load)
Volcano 11+
one stick 512 ddr ram
30gig had
CD-r
3.5 floppy
two Antec Case fans (dont remember the exact name.. they light up red. yay.)
Radeon 9000 Pro
cheapie sound blast card.

(currently nothing is oc'd)

Power Supply - Antec 300w Smart Power.

First i would suggest to reload your Windows(what ever you use) XP pro is no trouble.
And your PS with what you have on should be able to handle it NP My guess is something went wrong in windows