Help me become a PC gaming nerd

[Alby_da_Wolf]

@OP:
With my previous PC, an Athlon 2200+ (still an old 32bit one), 768MB RAM and Radeon 9250, I was able to play Gothic and Half-Life at max detail and 1024x768 res with almost no problems, while at the same res both Morrowind and Thief III had some hiccups in the most complex scenes, but I used Windows 2000, that ate less than 200MB with firewall and antivirus running and some services disabled. Your graphics card is more than twice as powerful as my old one, your CPU 40-50% faster, but if you have XP on it it should eat more RAM, so upgrading it to 2GB is quite necessary.
For the GPU you can get an overall idea here: http://www.tomshardware.com/reviews/gaming-graphics-card-geforce-gtx-480,2598-6.html
For the CPU, a 3200+ single core should be enough for old games, if the mobo is old I wouldn't waste money for ultrafast CPUs.
On my new PC I mounted an Athlon X2 5050e, an energy saving version, it requires only 45W, 20-30 less than my older and slower CPU, it's quite faster and powerful enough for games up to 2-3 years old at high settings, while it should run also most of the newer ones at lower settings.