Hi Justin,
If you don't have a decent power supply...you will never have a decent computer

It was a hard lesson that I learned...blew up my motherboard by doing exactly what you just did...
If you don't have enough power to run everything in your computer, it will cause things to die.
New motherboards and multi-core processors require the 20+4 pin power connector...if you don't have this, it is very dangerous.
If your power supply isn't up to scratch, and you can't afford a new one immediately. Don't use the computer.
The way I recommend people to upgrade computers - is start with a solid power supply...and then go budget on other things, power is the blood of the computer...think of it like our bodies working with not enough blood...we fail...badly.