If I understand correctly, you have a "now it works perfectly, and now it doesn't" problem. It sounds as if there is a program or utility loading and unloading in Windows that is interfering with your Word and Excel apps. When the item loads, they stop working. When it does not, they start working again.
> When you have problems again, open Wordpad and then Notepad. Do they work perfectly, or do you have the same problem with them? IF they do not work also, you have a system problem, not a Microsoft Office problem. Then try a system restore back to an earlier restore point before this started happening (if possible). Otherwise, I suggest a "Scannow" on your computer to (hopefully) find any missing or corrupted files.
> When you start having the same problems again, reboot and enter Safe Mode. Now use Word and Excel as normal. Use them for a long time period for a thorough test. Does the problem disappear, or is it still there? If suddenly you have no more problems, we know for sure that some software is loading that is causing interference.
> When you start having problems again, perform a clean boot, and load Word and Excel and use them for several days that way. Do the problems disappear and now no more problems? Then you have identified one of the msconfig items as causing your headaches.
[EDIT]: Forgot to add one more point: Before any of the above, carefully review any and all 3rd party utilites, add-ons or "really neat" software that you have installed from a 3rd party vendor. Those are a common cause of your type of problems. Try disabling them 1X1 to see if each may be the cause.
Edited by ranchhand_, 19 October 2017 - 08:45 AM.