Okay so my PC was running just fine and I decided to turn it off, i came back 30 mins later to find everything I type my password in to log on it loads then blue screens?
Yes. Unless you can take the hdd and put it inside another computer. If you dont have another computer you can take it to a repair shop or a friends place and get the files off that way.
Not if you do a repair install. Repair installs just replaced the corrupted windows files. Your files should remain. I always suggest backing your critical files up to a flash drive first.