Go
down the X10 route. If your BIOS supports start on plugging power use an
appliance module else one of the relay closure modules bridged accross the
switch wires. You would have to know that the release command had been
received though otherwise your button will remain pressed
in.
<<A universal X10 module can be set
to
do "momentary" (actually about 2 seconds) action when it receives an "on"
command...>>
Phil