I can't get my Wondows 10 PC to boot up because I made a big mistake. Everything was fine, no problems. I had an old pc and wanted to get some things off of the hard drive, so I put the old pc's hard drive into my current pc. It was recognized as drive H, I think. I was able to copy stuff off of it okay, but when the pc was turned off and restarted, it began booting up using drive H instead of drive C, which had Windows Vista installed. It right away went into System Repair. I held the power button until the pc shut off, disconnected Drive H, and powered back on. The pc wouldn't boot. Just stayed at the screen showing the dots going around in a circle. So the Windows Vista system repair did something. I powered the pc off and back on 2 or 3 times. It went into Automatic Repair, which seemed good to me. It's going to automatically repair, right? It said it might take up to an hour to complete. It did something for about 5 minutes, then went back to the screen with the dots going in a circle. Nothing seemed to be happening. I left it for 1.5 hours and it didn't seem to be doing anything. The hard drive activity light wasn't flashing. Nothing. Powered off and on again and got into a system repair menu. Went to Troubleshoot, Advanced Options. Tried System Restore, which said there are no restore points, even though I have used system restore before. System Image Recovery says there is no image file to use. Startup Repair can't repair the pc and takes me back to the menu. Not sure what to do now. I went into Startup Settings and tried to go into Safe Mode, but that wouldn't work. There is a Reset this PC option. Should I try that? It seems like a real pain because it will remove all programs that didn't come with the pc and reinstall Windows (8.1 I assume since that's what the pc came with. Then I'll have to upgrade to 10 again.). A lot of work for a few seconds of what Vista Repair did, and will be hard trying to remember everything I bought and/or installed. It seems like there should be an easier way to fix whatever the Vista System Repair started doing. The Startup Settings menu has a bunch of things, but I don't know what they are for. This is where Safe Mode was. Also some logging options, and some things to disable. Is there a simple solution?