IBM ThinkPad in Sleep Mode

I have a IBM ThinkPad i Series 1400 2621 44T that is in sleep mode and won’t come out of it. I have tried FN+F4, hold down the FN key when booting up and leaving the power off of it and battery out of it for 8 hours or more. I get the same thing every time. The little moon and the Z in a circle. Does anyone have any ideas how to clear it out of sleep mode?
Thanks…….Rod