OpSys for my laptop?
 

I have an IBM ThinkPad T41 laptop that I bought in 2004. Lately it has been slow, and the IBM wireless software sucks. I bought a new LinkSys wireless adapter, but that keeps conflicting with the IBM software.

I think I got rid of spyware, but I don't know for sure.

So, I think I might reformat the thing and start fresh.

What Op Sys to use? I hear MS Vista sucks --and it is expensive.

Are there any good low cost alternatives?

Win XP SP2 or Win XP Pro

Thanks. Where to buy it?