Verified answer

The best thing to buy to increase performance is a video card. If your motherboard only has an AGP and PCI slot I would consider buying a motherboard with PCI-Express slots and buy a video card for a PCI-E slot.

the hd is worth getting cuz you can use it on your next upgrade, but your system seems older, does it have SATA ports? if it does NOT, then i would suggest holding off on everything til you want to get a whole new setup.

SATA drives are the wya to do now, faster.

the video card is agp which is old technology.

if you were get a new CPU, its going to be an AMD which are not as good as the new core 2's. if you get a core 2, you will need a new motherboard, and new memory

that is why my suggestion is to hold off til you decide to get a whole new system.

you have an agp card, good to know, find the most up to date /greatest capacity you can afford,

buy bigger ram, but pay attention to the cl rating, it refers to data access time,

check the rpm of your hard drive, a faster hdd, will keep up better in high demand programs, if you're on 7200, save your money on hdds

no, memory(RAM) is just how much you can run at one time.

hardrive memory is how much you can store permanently.

the best thing I would recommend is another athlon with more speed (or just overclock your old one if you know how it won't cost you anything)