Ok grabbing more info :
first problem :
667 / 800 MHz Dual Channel Dual DDR2 SDRAM
regardless of what you put into it, that there will bottle neck most high end cards.
HDD Options , which do you have :
Hard Disk Drive options
160 GB2 7200 rpm SATA w/ 8M Cache
250 GB2 7200 rpm SATA w/ 8M Cache
320 GB2 7200 rpm SATA w/ 16M Cache
500 GB2 7200 rpm SATA w/ 16M Cache
750 GB2 7200 rpm SATA w/ 16M Cache
1TB22 7200 rpm SATA w/ 32M Cache
160 GB2 10K rpm SATA w/ 16M Cache
the only 2 that are good are the 32meg cache and the 10k rpm.
the 7200rpm with a 16 bit catch , kind of walking speed.
What card is in it now :
768MB DDR3 nVidia® GeForce® 8800 GTX
512 MB DDR3 nVidia® GeForce® 8800 GT
256MB DDR3 nVidia® GeForce® 8600 GTS
256MB DDR4 ATI HD 2600 XT
128MB DDR4 ATI HD 2400 PRO
if it is the 8800GTX, probably the best it is gonna get with the ram and HDD speeds. IF not an 8800GTX then I say upgrading is an option, but saving for a complete pc would be better. College is studying, not gaming
375 W standard
425 W available on select configurations
the two biggest things making it waste to upgrade is the RAM speed, and HDD.
I strongly recommend saving you pennies for a completely new pc, and just muddling around with what you have for a bit longer.
This is my opinion.
If you want to go nvideo card, someone can help you, I'm an AMD man