Are you sure the PSU and HDD are not faulty? Might be the cause of some of your problems... Especially I'd be wary of the PSU, suppose it gives some nice power spikes to the rest of the hardware?
You could check the SMART data from the HDD to see if it causes any of the problems.
The RAM is wrong, it's a kit of 2GB total: http://www.ec.kingston.com/ecom/configurator_new/PartsInfo.asp?root=fi&LinkBack=&ktcpartno=KHX1333C7D3K2/2GX
You probably want 4 GB with a gaming PC, especially if you have a version of Vista or Win7 that supports that much.