Interrupting long calculations in Excel?

Hi all,

I am having a very long calculation in Excel using VBA.

Of course I know I can hit ESC or CTRL+BREAK to interrupt the VBA
program.

But I found due to too long running process, the Excel window stop to
respond for very long time,

besically it's like "not responding" situation with "not responding"
on the windows title bar...

It doesn't seem to accept any more key strokes, not to say ESC or CTRL
+BREAK.

What can I do to rein/stop my program?

Thanks