Excel - vba - Shorcut Key: Is it possible to override CTRL+DOWN-ARROW ?

Hi.

I want a custom macro to be run when the user hit
CTRL+DOWN-ARROW

So, yes I want to override the default behaviour of excel on
CTRL+DOWN-ARROW

Is that possible?

I dont really think so as the shortcut is a standard default one for Excel. Why would you want to eliminate the shortcut and place your own in there?