Can't open files with LO.5

I recently started having trouble opening my files. I can make new files and open old files, but if I open old files, change them, save, and close, I can’t reopen. This is really bothering me, so I hope someone can help!

I run Windows 8.
I had LO.4 before, but then updated to LO.5, thinking it might solve the problem.

[Edit: add win8 + lo5 tags]

I assume you mean the opening in the file explorer. If the file icons are no longer associated with LO, you can fix it. Please refer:

Does that solve your problem?