OT: Sleep Mode (?)

[Jonathan Ryshpan]

I have recently bought a new computer and a fancy keyboard with many
keys I have never seen before.  I accidentally pressed a key at the
upper right of the keyboard marked "WAKE", which seems to have put the
computer to sleep.  Symptoms are that the monitor has gone dark
displaying "No Signal", and the power light on the computer blinks.
Pressing the power button wakes the computer up for about 5 seconds,
after which it sleeps again.  Pressing the reset button has no effect.

The salesman (Central Computer of SF) has told me that the machine has
gone into "sleep mode", which can be started in a number of ways.  He
didn't know how to get it out except by powering down the machine (using
the main power switch on the back), then powering up.  I asked him
whether there was any other way to wake it, and what use sleep mode
could be; he knew nothing, except that there may be a way to restart the
machine using the keyboard (but he doesn't know how).  I have a call in
to tech support.

Useful info may be:
        Computer is a white box using an AMD Phenom chip in an ASUS
        M3A78-EM motherboard.
        
        OS is Fedora-10 with all updates installed
        
        Keyboard is from DeLUX.
        
Any info would be much appreciated.