Why Is My Computer Running Slow

I feel obliged to upload videos since there are people subscribing to my videos, and expecting some videos to be posted. Here’s my first video. I have an old, slow computer so there is going to be a time gap between any two videos uploaded. Hope you enjoy this!

My computer stops responding with a black screen after windows logo showed up. How can I fix this problem? i run in safe mode and it works. Can I make a backup file in safe mode? Can I scan my computer in safe mode? How?