samsung focus stopped working

[darian key]

I went to go unlock my phone and it was off like most people say it happens. so i put it on the charger and still nothing, so i put the battery from my captivate thinking the battery is bad and still nothing only the samesung screen shows up but only when i remove and reinstall the battery. the phone WILL turn on if i press a bunch of buttons continuously though but once i stop pressing buttons itll work fine but shuts off about 6-7 seconds later. what is the problem?? i tried a hard reset but it wont stay on long enough for it to reset.