Photoshop wont save - move files. Error "not valid or name too long"?

Yes, my photoshop is licensed. All of a sudden, I cant move psd or png files. It gives me trouble - errors when I try to move them to diff. folders or save them to diff. folders. Says file is invalid, or file name is too long.. it will say too long even if it is just 1 character.... but here is the thing.. these files are ALREADY saved with the same file name / extension.. anyone have this same problem? Just started happening a few days ago. I have 4 virus spam scanners and they dont detect anything. I dont get it....