Any APM wizards out there?

I have a problem: When I use the USB keyboard and mouse the BIOS
no longer registers any activity, so after a while BIOS reduces turns off
the screen.
Well, I'd like BIOS to know that something is still happening while I use
USB.  Is there an APM call that I can use to tell the APM BIOS that the
machine is still being used?

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        -- Lennart