Hi. I have a mini PC in my car. I have it in the trunk and it's controlled by power switch that connected to the ignition. Turns on when I turn when start the car and vice versa.

I have it set to go into hibernation mode upon pressing the power button. When I press the button it goes into hibernation but upon starting the car and powering it up again, it reboots from scratch. It used to work but now it just boots a fresh startup.

How can I fix it?

Running Windows XP Home Edition on 512mb ram.