I still ran into the problem of it saying it wasn't compatible. So I've gone out and bought a new hdd. Do you know where I could download the original windows 7?
Legal Download from DigitalRiver: Windows 7 SP1, 13 languages
Get the x64 ISO for the version you have a key for (most likely Home Premium). They are all legit/legal, as they're from Digital River, a MS software distributor.