Nope, that's not it. Try getting a good power supply, one from a reputable company, I believe Antec and Fortran make very good PSUs. May be others but those are the ones I know about. I'm sure others will add to the list.
Antec also makes good cases BTW.
Every component in your PC is important, don't skimp on any of them. Not saying they have to be expensive, just be reputable.