Can't open dxf and dxf~ files

My computer was dead after Windows 10 forced update. dxf and dxf~ files done by LibreCad were therefore created
Fortunately, I managed to backup those files before my computer became useless.
After copying those files to my new computer also in Windows 10 with LibreCad newly installed, I just can't open those files.
"Cannot open file .....Please check its existence and permissions"
Very frustrated. Please help!

The error message is clear, if they exists, check permissions. If you don't know what they are, use google, that's not a LibreCAD subject.  

Sorry, I don't quite follow. What does 'permissions' mean? I was the one who created the drawing. Is it because I switched to a new computer? Is there a way to retrieve my drawing that I spent months on it?

You may try to open the files from within LibreCAD instead of the Windows file manager: File - Open.

Then also try File - Recent Files.

This is an issue often complained about with Win 10, but I don't know the exact abouts.

Also, check the file type box in the file open dialog. Be sure Drawing Exchange (*.dxf) is selected and not QCAD 1.x file (*.dxf).

Thx for your suggestion. I always open my drawing files in LibreCad
When I tried to open 'Recent Files', nothing could be chosen, maybe because I am using a new computer with LibreCad newly installed and never opened any drawing before on it.

I did, and no luck!

What happens when you make a new drawing with the new computer? Can this be opened again?
If yes you could then try to rename a copy of your old drawing to the name of a substitute  new drawing, which you already have reopened successfully. Just an experiment...

Actually, when I tried using your suggestion, I did a drawing and tried to save and had choices of saving as Drawing Exchange DXF 2007, 2004, etc. I tried each of them but after saving, the file does not even show in the folder!

Hmm. I'm quite clueless then. The only thing which comes to my mind is it might have to do with capital or small case letters. You might experiment with changing Renovation2 to renovation2. I have read Win 10 can be case sensitive.

Thx everyone for all your effort to help. My problem was finally solved by renaming my drawing folder from Chinese to English. LibreCad probably doesn't like a file with Chinese in it's path. Strangely, I did not have such problem on my previous computer.