EXCEL Alt shortcut keys problem

[mmserp_]

A couple weeks ago I noticed that Alt+[key] navigation shortcuts started replacing cell contents with odd symbols or cell address instead.

For example, Alt+[pg up] after navigating, I release the keys.  The destination cell now has a ´ (acute accent) instead of original cell contents. I also find  ♥ after releasing alt+[pg dn] instead of the expected cell contents.  Experiments with function key +alt +[key] did not fix the issue.

Was there something in the last update that broke alt shortcuts navigation?

How can I restore alt+[key] to original settings? 

[#2]

NumLock not the issue here. All my navigation shortcuts ([Ctrl] + [End], [Ctrl] + [Home], for example) work. EXCEPT the [Alt]+ [key] ones. No difference whether I use the NumLock versions or the keyboard's dedicated keys.

2d FWIW: After 20+ (probably 27 but stopped counting), full XP system recoveries including software installations and TWEAK.UI registry edits, I've developed many troubleshooting checklists and a wicki file to try before asking forums for help. Added to those checklists during Windows 7 and now Windows 10. And why I suspect that last Windows 10 update broke something.

[#3]

@mmserp_ 

Hey, did you ever find a solution to this? It is driving me crazy. I copy/pasted a bunch of data from a USGS website, and was having issues getting the data to be recognized as numbers. Alas, a 10 year old post: https://answers.microsoft.com/en-us/msoffice/forum/all/excel-not-recognizing-numbers-in-cells/d4ee1a...

 gave me the answer. Pasting ALT+1620 into find/replace removes an odd space size and allows excel to recognize this text as a number. Worked on my first chunk of data yesterday. Came back today, to apply the same fix to the rest of the data, and instead of a space entering the "find" dialogue box when I type in ALT+1620, I get the letter "T". Tried typing it in as ALT16+ALT20, different combos, etc, and got a bunch of wingdings, etc. 

I think we have the same problem. ALT+1620 worked yesterday, now "T" and various symbols are replacing ALT+ functions in the find/replace box. Please tell me you found something!

[#4]

No. The suggested fixes either already tried before posting, didn't work or were too drastic.