Erm im not sure i would be buying XP for that price with win7 out and probably available for not much more.
If your building a pc you need to check that all your hardware is compatible.
In terms of the OS there is no reason at all why it should be incompatible. And no the drivers are installed once you have installed the OS.
My advice wwould be to google "how to build a pc" and "how to install an OS/win XP"
Good luck, and if you get stuck just ask