Hi, I am new to these forums but hoping I can get some help regarding my desktop iMac. I've had it since the Fall of 2005 and have had virtually no trouble with it at all. But the last few weeks, it has all of a sudden done strange things like turn off all by itself while I was online, or when I walk away for an hour or so and then come back to it, instead of being in the "sleep" mode or me being able to just move the mouse around to bring the screen back, it has again turned itself off. Yesterday, I was using it fine, went out for a while and came back and it was off, but this time it would not turn back on again. I tried unplugging the power cord a few times, but this did not work to get it going. I tried just holding the power button and the light on the bottom right-hand corner flashed on for a second, but the screen still will not go back on. I am not getting any types of error messages or anything on the screen at all, it is just blank. Am trying to see if it is a battery issue or something to do with the power cords. Any ideas as to what could be causing this issue?