Software to view system configurations?

I have a project to upgrade a network from NT4 to W2K. There are at least 20 client machines running a variety of Windows versions including Win98, Win NT 4 Client, Windows 2000 and Windows XP. My plan is to use W2K Server on the servers and WinXP Pro on all clients.

Are there any programs available (at a reasonable Price – under $200) that I can use to check each client machine for compatibility with XP? In other words, I would like to quickly determine each machine’s cpu, ram, video adapters, modems, etc.. to se which machines need to be completely replaced.

Thanks