Upgrading Computer -- Hello

[Hapless]

Hello to everyone, im still new to the business of custom computers. I built a custom computer 3 years ago with the help of a friend and now the motherboard has died. My computer's set-up was purchased from New-Egg and is as follows:

Chassis: Enermax, CS-3171L-B3A (Black/Silver) "Rainbow Light'' Aluminum 10-Bay ATX
Hard Drive: MAXTOR 60GB 7200RPM EIDE HARD DRIVE MODEL # 6Y060P0
Ram: GEIL 256MB PC-2700 (333MHz) DDR RAM, 6 Layer Ultra Low Noise Shielded PCB, 32x8 Low Density/Unbuffered, Model# GE2562700
(I've upgraded my RAM to 1 gig since)
Mother Board: MSI Motherboard for AMD Processors Model K7N2 Delta-L
CPU:AMD ATHLON XP 2400 /266 FSB PROCESSOR CPU
Heatsink:Thermaltake VOLCANO 11+ Xaser Edition. Opti-fin technology, made of All Copper.
GraphicsOWERCOLOR ATI RADEON 9800SE 128MB DDR DVI/TV-out 8X AGP
CD-ROM: (I've Switched them out to dvd-rom and a dvd burner)

I'm looking to upgrade whatever i need to improve preformance on newer pc games, even if its only slightly and i've got a 500 dollar budget, max, but it would be great if i could keep it under that

--on a side note was i suppose to of gone somewhere for the introductions?

 

[The_Prophecy]

CPU: AMD Athlon 64 3500+

Mobo: Asus M2N-E

RAM: G.Skill 1GB (2 x 512MB) DDR2-800

Video: eVGA Geforce 7300GS <--- If you want better video performance than this card provides, get it now and wait for the DX 10 cards to show up (approx. 6-8 Months)

Case: Antec Sonata II

Total before taxes and shipping: $490.96

Edit: When you get more money later, consider adding the following parts to this build:

Hard Drive: Seagate Barracuda 7200.10 320GB SATA2 <--- This one would be a VERY good idea.

DVD Burner: NEC ND-3550A

Monitor: LG L1752TX