Hi I've just bought a secondhand mac book pro 4.1 the battery is completely dead but worse the fans are on constantly running at 6000rpm. I've tried resetting the pram and the smc but nothing changed. I can't get the hardware diagnostic tool to work, it will run but freezes when it gets up to running checks on the logic board and i have to unplug the power to turn machine off. I'm hoping I haven't bought a dud machine, any advice greatfully appreciated? Oh and I only have the second install dvd which may prove to be a problem..