Hello Sorry new guy here, and I am going to try my best to not ask any stupid questions. I have been reading the forum for a few hours, but hoped you guys could help me out. I had windows 7 x 64 cd that broke. I wanted to download windows 7 x64 (Also 8.1 x64 if it was possible) and put it on USB drive so I can re install windows if need be. 1 of my computer came with Windows 7 then other 2 are older (XP and vista). 1. Which version of Windows 7 x64 should I download would be easy to activate on all the computers regardless of what came with them originally? 2. Also the same question but with Windows 8.1... 3. Can I put 8.1 and 7 on a USB drive and then choose which one I want to try out. (I assume the answer is yes.) Assuming that answer is yes do I need any special program in the stick, or just the iso files? 4. How big would the USB drive have to be to have both 8.1 and 7, would 8 GB do it? Thank you again for all the help. I appreciate it.