About 6 months ago my Macbook started shutting down while it awoke from sleep mode. When I close the lid or it goes to sleep on it's own the light flashes on and off indicating it properly when to sleep... but as soon as I open the lid or touch a key to wake it the whole thing reboots. It happens about 75% of the time so it's really really obnoxious. Battery health is at 87%, and the problem still occurs whether it's plugged in or on full battery... so it's not a batt issue. I've researched and tried everything, including clearing the CMOS (or whatever Apple calls it) by removing the battery and holding the power button down. I've even replaced the hard drive and did a totally clean install of Leopard. I'm currently using 10.5.2. Anyone out there experienced this same thing or know what is causing it?