Backspace key changing last letter to x and then not deleting further

If you run the NirSoft program HotKeysList (free download) it will tell you if the backspace key has had a shortcut associated with it (which is what I suspect is causing your difficulties). Try it and see if anything comes up for backspace. If so, we'll then have to figure out how to cancel that assignment.

L̶o̶o̶k̶s̶ ̶l̶i̶k̶e̶ ̶t̶h̶i̶s̶ ̶i̶s̶ ̶c̶o̶v̶e̶r̶e̶d̶ ̶i̶n̶ ̶a̶ ̶P̶C̶ ̶M̶a̶g̶a̶z̶i̶n̶e̶ ̶s̶t̶o̶r̶y̶ ̶c̶a̶l̶l̶e̶d̶ ̶"̶M̶a̶n̶a̶g̶e̶ ̶Y̶o̶u̶r̶ ̶H̶o̶t̶k̶e̶y̶s̶"̶ ̶w̶h̶i̶c̶h̶ ̶e̶x̶p̶l̶a̶i̶n̶s̶ ̶h̶o̶w̶ ̶t̶o̶ ̶u̶s̶e̶ ̶a̶ ̶f̶r̶e̶e̶w̶a̶r̶e̶ ̶p̶r̶o̶g̶r̶a̶m̶ ̶c̶a̶l̶l̶e̶d̶ ̶H̶o̶t̶K̶e̶y̶ ̶D̶e̶t̶e̶c̶t̶i̶v̶e̶ ̶2̶ ̶t̶o̶ ̶f̶i̶g̶u̶r̶e̶ ̶o̶u̶t̶ ̶w̶h̶i̶c̶h̶ ̶p̶r̶o̶g̶r̶a̶m̶ ̶"̶o̶w̶n̶s̶"̶ ̶t̶h̶e̶ ̶a̶s̶s̶i̶g̶n̶m̶e̶n̶t̶,̶ ̶s̶o̶ ̶t̶h̶a̶t̶ ̶y̶o̶u̶ ̶c̶a̶n̶ ̶c̶a̶n̶c̶e̶l̶ ̶i̶t̶.̶

Drat! Looks like Hotkey Detective 2 is NOT free, and isn't terribly trustworthy or reliable, either. It's looking like a Ziff-Davis attempt to extract money from readers and users like us. Sigh. Does anybody know if AutoHotKey (a known, good, working hotkey management tool recommended by many TenForums regulars) can help this person figure out in which program the hotkey may have been assigned? Sigh again.
HTH,
--Ed--

PS: sorry for the false lead. I should've chased it all the way to ground before saying anything about it. Sigh yet one more time.

PPS: I found a SuperUser thread that addresses this issue in Windows 10 with a Visual Studio tool, but it doesn't look like something that will appeal (or make sense) to casual, non-power users/non-developers: keyboard shortcuts - How can I determine which process owns a hotkey in Windows? - Super User. Zounds! This turns out to be a tricky and interesting problem. Your 3-year-old is obviously headed for a future in the computer biz...