I have a laptop to fix (Acer Aspire 7530) and it behaves really strange. When it is restarted it shuts down instead (automatic restart during Windows installation, manual restart when Windows runs - all behave the same, the laptop always shuts down). When it's turned on immediately after the power off, the status LEDs light up for a second or so but then to laptop turns off again. After-a-while power on shows the splash screen and BIOS is accessible, but the Windows doesn't boot. After a longer while left off (15 mins), the laptop starts and Windows boots and works until next "restart" (or BSOD).
Whether there is battery present or the laptop is AC powered, the behavior is still the same. There are no power management settings in the BIOS, but I don't think this is SW issue. I have also reinstalled Windows (just in case) but it didn't help either. I also had the laptop apart for fan/heat sink cleaning (lot of dust there) but the dis/assembly process didn't change the laptop's behavior either, moreover the inside parts look OK (the motherboard is not broken, all cables seem to be in place). The diagnostic of the HDD also showed no errors.
Has anyone seen something similar? Do you have any ideas what might be the root cause? I'm guessing malfunctioning motherboard, but that would be the end for the laptop (it's probably not worth $150 repair).
Any help is greatly appreciated.