sinclair_tm

i believe you have a hardware problem and should be taking it back to apple to have them fix it. most likely there is a short in the keyboard, and even if the key isn't stuck, the computer thinks it is, and so it keeps it going. best way to find out if that is the case is to disconnect the keyboard, and plug in a usb keyboard and start the mac. if the problem is gone, then you need a new keyboard. as for the other issue, you may need to reset the pmu. evey mac is different, so look in your owner's manual for the instructions on your mac. and if the keyboard is messed up, then you may not be able to reset the pmu, and thus the power issues.