How old is the motherboard? If newer than few years, you should see a flat, shiny, disc about the size of a quarter. Carefully remove this and get a new one (about $5.00 USD), the type number will be on the battery. Before you do this, when the computer first boots up, go into the BIOS setup and write down all the settings. When you replace the battery, your CMOS will reset to "Default", which may not recognize your boot sequence and see the Promise board. If you're not familiar with what settings mean what, you may need help from a friend (who does know), or even take it to a repair shop.