With exact computer model # we'd be able to look up what it originally had... Also, if your having to go out and buy an OS, I'd suggest throwing the towel in on Windows Vista and using Windows 7 instead. Its way better, but you will want to have minimum of 1GB Ram, although I like 2GB minimum for 7. With computer model info and ram amount we'd be able to verify Win 7 drivers available and 32 or 64 bit operation.