Windows cannot find C:/ ..........

Hi,

Since a couple of weeks ago I've been having some issues with some of my programs that just won't open. I get the message "Windows cannot find "C:/..[NAME OF APP.EXE]" please make sure you typed the name correctly". I've searched for A LOT of solutions online and nothing helps. This is not for a specific app, but for several (had this issue with Anaconda, MS Word (only Word, Excel works without a problem), and now ArcGIS Pro. I've uninstalled and re-installed these programs, and could only get Anaconda to work. Still no luck with MS Word or ArcGIS Pro. Not sure what to do with this. Btw, all the files that say that "cannot be found" are there.