Computer shuts down. and the longer i leave it of the longer it stays back on wnen i start up

Question

and the longer i leave it of the longer it stays back on wnen i start up again,if i try to start it up straight after the pc has shut down it just lights up and shuts down again,any idea's to this solution welcome,my computer is a amd athlon duo core,ps i try to check the bios but it wont stay on long enough to really do any checks.