I was wondering if these products are decent for a gaming computer?
Anything i should change?
AND MOST IMPRTANTLY!!!! ARE THESE PRODUCTS COMPATIBLE W. EACHOTHER?

AMD Athlon 64 x2 4800+ (Dual Core) 64 Bit Socket 939 1024K Cache (Magic MICRO)

GeForce 7100GS 128Mb PCI EXpress 16X dual head, tv out
(Magic MICRO)

ASUS A8N-SLI Deluxe nForce4, PCI-EX SLI, DDR 400,SATA, 1GB LAN, iEEE ( Magic MICRO )

then, i have one 160g, and one 80g hard drive.(dont know exact speed)

also i have 2g of ram.

Yup, looks like all those components should work fine together. But you might want to consider going with a socket AM2 instead of 939--the CPU's are much cheaper. Unless you have some very high quality DDR (you mentioned you have 2GB on hand, but is it good?), then it might be worth it to go AM2 and get DDR2 because the 939 CPU's are much more expensive.

However, in my opinion, if you want to play any sort of newer game (like from the last year or two), you're going to need A LOT MORE than the 7100GS that you linked. Anything under 256mb of VRAM isn't really a good card for any sort of newer game. If you want to spend $200 or less for a good card, you should get either an ATI Radeon x1950pro or an Nvidia Geforce 7900GS. They both play games like FEAR at high resolutions/detail very smoothly, and don't cost an arm and a leg. They're both pretty equivalent cards, and you can probably find them pretty cheap online--if you're in the US, I recommend going to newegg.com--they seem to have a much larger selection of--well--anything compared to the website you linked the components to.

Also keep in mind that games rely heavily on the CPU's level-2 cache--so the more the better. I'd actually recommend going with the slower 4400+ socket 939 (that's what I have) because it has 1MB cache/core instead of the 512k cache/core that the 4800+ has--and it's easily overclockable to the speed of the 4800+ on stock cooling with the right motherboard. That's why I chose the "slower" 4400+ over the faster 4800+ at the time. Just something to keep in mind.

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AMD Athlon 64 X2 4400+ (@2.6 GHz)
2x1GB OCZ Spec. Ops. PC3200
ASRock Dual939-SATA2
Antec TruePower 550 watt PSU
80 GB Seagate Barracuda SATA 7200 rpm
300 GB Seagate Barracuda SATA 7200 rpm
120 GB Maxtor ATA/133 7200 rpm
ATI Radeon x1950 Pro