Sorry, I'm new (obviously) so I hope I'm posting this correctly. I have a Rev. B MacBook, 1.83 GHz Intel Core Duo processor/512 MB RAM, running 10.5.7, and for the past 6 months or so, it has been constantly kernel panicking - sometimes it just freezes, other times it gives me the "You need to restart your computer". These crashes happen the same way every time: the computer will stutter (cursor disappears/reappears, any sound/video playing will pause/unpause) and then a minute or two later, it kernel panics. It crashes while I'm doing anything - Photoshop, iTunes, Safari/Firefox or MSN. No specific thing will make it crash. In the past 4 hours of using this computer it has kernel panicked 3 times. I would guess that it crashes roughly once every 2 hours normally. I have replaced the hard drive and reinstalled the system software countless times. There are also problems with the AirPort Extreme card - I'm not sure exactly what the issue is quite frankly, but occasionally when I reinstall the system after another crash (blinking system folder at startup) the AirPort card does not show up anywhere (not in Network, and the AirPort menu says the card is 'not configured') and I have to reinstall the system... again. It's hit-and-miss. Again, I apologize if I haven't posted this right, and I hope the length isn't too daunting. Thanks in advance for any help.