I have an Acer Aspire 5750Z-4830 laptop that will not boot up. When you press the power button, it boots up to the Acer screen for a couple of seconds, you hear a whirling sound (hard drive?) and then it shuts down. I have tried it with and without the battery installed. I can hit PF2 and get to the BIOS screen for a second before it powers down. Running Win 7.