I am a real dummy with this stuff. I bought 2 used computers at auction. They are Dell OptiPlex 760, 3.16 GHz, Core2Duo, 4Gb Ram. They have been sanitized and have no operating system on them. They originally had Windows Vista on them. I have been to EBay and there are a lot of products there, but I don't understand the differences and what the sellers are trying to tell me. Even when I asked a seller a question, I didn't understand the answer. The issues revolve around the license key. I just want to install an OS, legally and cheaply. But I don't necessarily want Vista, if I could put Windows 7 on them cheaply. I see ones that come with a harddrive. I see one that comes with a broken motherboard, WHAT?? It is brand new in the box?? I see restoration disks, upgrade disks, disks with and without product keys, COA's. What does it all mean? What are my options and what do they cost? Thanks.