As far as Ctrl+v, I'd change the shortcut key so that it no longer over-rides the default behavior and as far as the rest of the code, I'd try
only on each command bar item originally changed and see if that resets it. (Not gonna test it as I don't want to be stuck with the same problem.) If reinstalling Excel didn't solve the problem, I'm guessing that you'll have to deal with some Registry entries. Type "Regedit" at a command line to get into the registry editor, but be careful in the registry editor, you can wreak havoc if you don't know what you're doing. Set a system restore point before you make changes to the registry. The other thing to check is Users > YourUserName > AppData, not sure that's the correct path, but once you get to that folder, check around for an Excel folder, then take it from there.
As far as a solution to your original problem, I'd need some more info, but two things you can try is 1, put your macro into the Personal Macros workbook, which then will be available whenever Excel is open, or 2, in the workbook you have your macro in, use the Workbook_Close event to cancel it being closed unless all other workbooks are closed. Something like this:
Sub Workbook_Close(Cancel as Boolean)
If Workbooks.Count > 1 Then
MsgBox "You must close all other workbooks before you can close this one."
Cancel = True
Hope that helps