i have windows xp oem 64 bit. but i am afraid to install it coz it might not that be good and if i installed and i dont like it, i wont be able to sell it anymore. so which is better, windows xp 64 bit or windows xp protessional? pls help me decide!

Stick to 32bit (professional), because support for 64bit is still very rare, there are only a few applications that can take advantage of 64bit and your 32bit programs will run a little slower because it has to emulate 32bit.

I'd stick with 32bit until Windows Vista comes out (around February), by then there'll be 2 versions, 64bit and 32bit and there'll be much better driver and application support!