Hi there, I have a toshiba A75 laptop that does not boot when on ac power without a battery beyond bios. It shows the splash screen but then dies on normal boot. When I have the battery in and the unit is powered off It does charge the battery. When the battery is fully charged, it will run and boot into windows but does not recognize the ac power at all. It just drains the battery, then when the battery is at 0 it shuts off and this is while connected to AC power and the LED see's the AC power. When on AC power I can boot into bios and it will sit there for days without a battery, but when I try to get to the OS it just shuts down. I have replaced the mobo twice. I have replaced the hard drive as well. The odd part is that with the hard drive out of the laptop, I can get the laptop to run with out any power failures. It just recycles the media device failure message but does not crash. I have tested the power supply on other laptops and it seems to work just fine. Any one have any ideas?