AWOL? I'm sorry?
Is it like getting reset? Then it's your Motherboard battery, which gives a bit of electricity to your BIOS chip to get stored, and the BIOS chip includes the time, so when the battery doesn't give power, nothing gets stored, including the time.
Try reading this for howto replacing your motherboard battery:
http://www.ehow.com/how_8159_change-battery-computer.html