Missing files, how do I fix this?

Ok, so I wonder what happened here.

I had one hard drive with this project that I was working on (everything was on this drive). I added a different project to the same hard drive (meaning raw media, library, event and project)
As the hard drive was getting full I copied everything to a different drive as well, but didn’t delete anything. But what happened here. I didn’t move anything either BUT what happened is that the project disappeared so I had to find it though opening different libraries from backup (from the top menu) when I tried to open it now, this happened. So how do I get the media back so it’s working again?

Trying to insert a pic of how the project looks like (don't seem to work) but lots of the clips says "missing file"

Ok, so I moved the project to the original library and it seems to be working now. Cause when I tried to restore the projects it kept making new libraries.