Why can my computer start safe mode but not normal mode?

This question is hard to say. There may be many reasons. You said it would work in the computer city, but not at home. I suggest you test the power supply at home. Is it unstable or disturbing? Because you haven't moved anything, the only difference is that the place is different. Safe mode itself is the most basic \ minimum power consumption startup mode of the computer, so it won't occupy too many resources.

On the other hand, did you touch the computer on your way home? Poor card contact may also happen to you.