Using Win8.1 for just a day messes with your separate Win7 setup.
Using Win8.1 for just a day messes with your separate Win7 setup.
I've tested compatibility mode in Windows 7 but it didn't help. Some games in Steam didn't run properly, yet they worked when told to run in compatibility mode. It seems there might be a hardware problem, maybe related to your hard drive. Even after a full scan showing no errors, issues can still occur. You could try splitting a portion of your 1TB drive and see if the problems persist during installation.
You configured Windows 8 for dual boot, made Windows 7 the default, and set a timeout of 5 seconds. After a few days, you booted into Windows 8, restarted back to Windows 7, and later encountered issues. You considered trying it again in the future but decided to give Windows 7 the entire 1TB drive for your games before taking a break. You also explored a comparison between a laptop and a desktop using the provided link.