i think its your ram holding u back u only have 512mb ram, and its PC2700, u need at least 1 gb (PC3200 or higher) man. i c that ur getting some soon, so hold out on beatin the hell out of ur comp...try the ram see if that works, if ur just going to get anohter stick of 512.... make sure u get 2 pc3200's and not use a 3200 and a 2700, cuz ur computer is only as strong as ur weakest link...
Sony Vaio RS-620G
Pentium 4 HT 3.0E Ghz 800MHz FSB
1024 MB Ram PC3200
160GB Hard Drive (7200 RPM)
ATI Radeon 9200 128MB (Putting the 9800 Pro 128MB back in hopefully soon)