Unreadable Characters found in my USB Drive Folder / Files

I have encountered this problem before and until now I can't find a solution for this. I always found a folder or files on my USB with unreadable symbols / characters/bytes. I can't understand why is it happening and my USB really suck when this file are present in my USB drive it shows an error message " Device IO input error" blal.bla..blah..

I can format my USB drive and those files can be remove but it will still a mystery for me. Anybody can help?
Luckily, I have a screenshots below and check what those stuffs appearing there.

When I have this files inside my USB drive, I have no choice but to Format and some files could not be readable anymore (Corrupted).

Update : I scan my USB Drive to spot any threat
              Malwarebytes - no threat found
              SuperAntispyware -no threat found
              USB Virus Scanner -no threat found
              Avast 5.0 - detect my word file ( project.doc) as a virus- BV:voff- gen.what's this? I never found references on the internet about this detection.


Is my Flash Drive is infected by threat? what threat?How to solve it?
Please feel free to comment for solution.