This has been going on for a while. It happened first a month or so ago. I turn on my 2008 iMac 24". The screen turns white like always, but no Apple icon appears. It starts to make a loud nice again and again. Bip, Bip. Pause. Bip, Bip, Pause. Bip, Bip. Pause. I turn it off. Turn it on again. Same thing happens. Repeat. I take out the cable powering the computer and go to school. I put it back in when i returned and turned the computer on. It worked fine. Nothing happened again until a week after. I was sitting working on the computer, when it out of nowhere shows the "grey screen of death". I turn off the computer, take out the cable, leave it out for half and hour or so, then turn the computer on. It works fine. Works for a week. Same thing happens again. Now it starting to appear more often tht though, and I'm afraid to turn it on until i get an external HD so i can Time Machine, in case it will appear more often for every time i turn it on. The guarantee is not valid anymore (never purchased AppleCare) and i can't bring it to a store and show them what it does, because it doesn't always happen. I read that it might a kernel panic somethingsomething, and that i need to wipe the HD. Though that was when the computer had the grey screen all the time. Not just occasionally like on mine. Does anyone know what's wrong with it? How to fix it? Thanks in advance.