What is best operating system for gaming Xp or Win 7

If you are running older games, it will be XP.
Win 7 will work fine, but older stuff, like your printer, camera, old games, may not run as before.

For older games go with XP, but if you want to play newer, latest games, it's Win 7 all the way. It should work on your system.

Win 7 is just fine, but I have trouble with older software and hardware. I think I would have rather kept win 2000 pro.

Lol. If you are gonna run Windows 7, grab another 2 gb of ram. I've got Vista and just bumped my old dual core desktop to 4 gb of ram(Athlon x2 5400, 4 gb of ram, 9600gt). And it's pretty quick now. Ram is cheap enough as well. That's what I'd do personally. XP was great, but is now old and going to be more unsupported as time goes by, plus you can't use dx10 and dx11 with it either.

Win XP is great for games, but some developers have started to drop support for DX9 like Just Cause 2 and Battlefield 3. You need at least Win Vista to play games like that.

Actually, Halo 2 was the 1st game you could not play on Win XP even though it was a DX9 game. Microsoft used it to force people to upgrade to Win Vista by integrating Dx10 code into the game.