Hello, I (The actual purchaser was my brother-in-law for my sister not me as stated throughout) had purchased a MACBook Pro approx. 1 & a half years ago for a pretty hefty price through Kijji off of some person. It recently died. My friend told me to take it to a computer shop nearby to see if they could fix it. When I get it back, I notice that it use to have a 9600M video card and now it has only an 8600M video card. This unit has bootcamp installed with XP Pro on another partition. When the power adapter is attached, I can use it, but can no longer log into the MAC OS, all I get is a spinning wheel of death. I can log into XP but when the power adapter is removed, the unit just suddenly dies. What is the problem here? I was just thinking that because the video card is integrated, this computer shop had fixed the unit by simply replacing the motherboard with an older, cheaper model with a less efficient older video card. Now if the motherboard had been changed, the HAL (Hardware applications layer) has also changed and is no longer compatible with that of the prior motherboard that had the 9600M video card and therefore, I can no longer log into my MBP and will have to reinstall the MAC OS. This is perhaps the same condition that the XP OS is faced with and that is why when the power adapter is removed the MBP dies. What type of complications would I be faced with in the condition above where the original motherboad on the MBP had a 9600M video card and the new motherboard has an 8600M video card? If the hard drive was left the same why can I no longer log into my MAC? If the moterboard has been changed when the power adapter is disconnected should the unit just suddenly die like it does? Its as though the power adapter is not charging the battery or the motherboard is not realizing that the power adapter has been disconnected and auto switch to battery power, or there is a faulty inverter board on this new motherboard which does not charge the battery period. The OS that is currently on and prior to its breakdown is Leopard 10.5.5 Need some help to figure this one out.