Reset Ctrl+ Macro Shortcuts
 

I wrote a macro and assigned it Ctrl+b (lowercase b). After realizing that
it was also the command for Bolding text, I removed the shortcut, and even
the macro itself... but now, whenever I Bold text by hitting Ctrl+b, Excel
seems to freeze for about 10 seconds, as if it is looking for the macro I had
previously assigned to that combination.

Is there a way to reset these commands, or restore defaults, or something,
so my computer doesn't hang every time I hit Ctrl+b?