Photoshop 7 suddenly stopped working

Hello,

I have a copy of photoshop 7 that suddenly stopped working. it was functioning fine this morning, but when I went to use it this afternoon, I got the error message "Windows cannot access the specific device, path or file. You many not have permission to access this file. I am the administrator on this computer and there is no reason to not have permission. Don't understand what happened. is there a way to re-download it and re-install it? Thanks