[G4] Force quit has vanished -- help!

[David Minger NPG Cable]

I have a G4 450 with 1.5 gig of ram running OS X 10.4.1.1

I also have a Mail application that keeps hanging up. I've wanted to  
force quit it a number of times. Problem is this: option-command- 
escape does _nothing_ -- it does not any longer bring up the force  
quit menu.

Any suggestions?

Best,
Dave in Flagstaff