well, your pretty limited in what you can do with that system Im afraid. your motherboard supports up to 4 gigs of PC3200 ram (400 mhz) so you could upgrade that to bring up your performance a bit, though keep in mind you will need a 64 bit OS to recognize the full 4 gigs, a 32 bit OS which is what you have will only recognize about 3.25 gig or so. and being standard DDR, and most modern games are made to run on DDR2 or DDR3, will affect your gaming especially with larger games like Crysis. Also, your computer only has an AGP 8x slot, so your choices in video cards are limited to AGP cards only, and even further limited by your 250 watt PSU you have in it. Probaby the best card you can throw into it is this one
http://www.newegg.com/Product/Product.aspx...N82E16814130210 and it will probably tax your PSU pretty good, Id be hesitant with it. If you upgrade your PSU to a good 4-500 watt PSU this is probably the best one you can throw in there:
http://www.newegg.com/Product/Product.aspx...N82E16814161284. as far as the processor is concerned, someone correct me if Im wrong Im not finding anything stating otherwise, but I believe that your system uses the intel 865PE chipset, which only uses socket 478, so your processor upgrade is limited, at best. No dual core support whatsoever, in fact they dont even manufacture 478 CPUs anymore so youd have to find one used off ebay. Personally, my recomendation is if all you want to do with it is college and blogging, upgrade the ram, and it should do everything you need it to fine. If you want to use it for any seriouse gaming, build a new computer. If you just upgrade the ram, I would use this it should be compatible with your system and Patriot has always treated me right.
http://www.newegg.com/Product/Product.aspx...N82E16820220040