Never want to hear Windows' command line window scold you with that awful error beep again? Microsoft MVP Aaron Tiensivu has two one liners that will silence the speaker beep:
net stop beep will disable the beep for your current session, and
sc config beep start= disabled will silence the beep for good. (You've got to be logged in as an administrator to run these commands.) Of course if you're serious about the command line on Windows, give Cygwin a try, which, by default, doesn't beep at you.