ignoring certain keys?

[Arclight Media]

I am trying to build an app that will ignore when a user presses the windows
key on a pc, which would normally make the system lose focus on the app and
bring up the taskbar.  Is there a quick way to do this, or to make sure that
the app is always being focused on?

(I am having the keys play sounds, and would like to ignore any other than
letters and numbers, and am currently using the "onkeyup" handler, which is
working great except for the above mentioned key.)

Thanks!

Mark