Is windows vista or windows 7 available for this system requirements?

I was running Win 7 Ultimate x86 on an old PC with a 2ghz AMD proc and 768mb Ram (a 512 stick and a 256 stick)... had a junky radeon x1600 AGP video card and IDE drives... it was pretty choppy playing WoW at even the lowest settings, it was alright for basic web surfing, but flash games like Cafe World were barely useable and took forever to load. I think you could get it to run, but you wouldn't enjoy it, and Aero might not even work right on a 128Mb gfx card. This is definitely an XP level setup. If you want to try linux there are a ton out there that would work fine with this hardware. Damn Small Linux and Puppy Linux would probably both be very fast on that hardware, as they don't need much.