Display Turns Off, Computer Sleeps.. I Think


i'm using a powerbook g4, one of the early 2001 models, 667 mhz w/ 512 ram and 133 mhz system bus.

i have just installed mac osx 10.27 (jaguar) and i reinstalled the os because i was having an issue w/ the display turning off.

now it seems that everytime i hit the command key to the left of the space bar, the screen turns off. sometimes the computer merely sleeps, so that when i hit spacebar, it comes back on as if on steady state off mode.

however, sometimes it won't come back until i've either popped off the battery and reinserted it and then turned it on; or if i hold the power key til the system turns off, then turn it back on *mind you when the screen goes blank, it sounds as if the computer is off.

the screen goes black but it usually still has a ghost effect of everything i was last viewing... almost like a burn in but not possible as LCD's take atleast 15 to 30 seconds to burn. (or so i was trained when i used to sell LCD tv's.)

if anyone could help, i would greatly appreciate it.

i've looked up a few things on the net that tell me install firmware before the installation of 0SX 10.27 but i dont have another OS to give me that luxury; and my friend who believes himself to be somewhat of a computer buff, is stumped and doesn't believe it to be firmware related.