I've probably asked like half a million people this already:

I can see a few oddities with your parts selections.

First off, it's a really bad idea to trust any computer to a shonky $25 power supply. NCIX sells a decent 400 watt Fortron/Sparkle PSU for $43, and it'll pay for itself many times when it doesn't blow up and kill your shiny Athlon 64.

The Seagate 7200.7 line is very quiet and very reliable, unlike Seagate's crappy new drives, but the 120GB model has a lousy price:capacity ratio, and it's a bit outdated. This 160GB Samsung is cheaper and larger than the Seagate, has SATA 2 support, and shares the 7200.7's low noise and good reliability.

The Asrock board is a surprisingly good performer, but it's a bit of an odd choice if you don't need an AGP slot. I like the Chaintech VNF4/Ultra, since it's cheap, fast, and capable of stupidly high (350+ HTT speed) overclocks if you know what you're doing. If you're sure that you don't want to overclock, the Asrock board is probably a better overall choice thanks to the lovely ULi chipset.

Jam it back in, in the dark.