It is a shame that the power button in Windows only brings down the shutdown choices. What good is that for a remote? Anyways, it is possible in Windows to assign a button to run a program.
To run the Windows Shutdown script:
C:\WINDOWS\SYSTEM32\SHUTDOWN.EXE -S -T 03 -C "SHUTDOWN INITIATED BY ATI REMOTE WONDER" -F
To restart the computer:
C:\WINDOWS\SYSTEM32\SHUTDOWN.EXE -R -T 03 -C "SHUTDOWN INITIATED BY ATI REMOTE WONDER" -F
These commands are for Windows XP and Windows 2k. I do not know offhand the commands for Win9x systems. This also requires Remote Wonder software v1.2 available from ATI's website.
HINT the "a" and "b" buttons are close to the power button on the remote making it a good placement choice for shutdown.