Must restart to correct booting

Hello,

it doesn't restart

whenever i try to restart my pc

all the fans start spinning ,hard disk spins, the drives are working
but the monitor does not start and the motherboard doesn't give the normal start beep.

But if i switch off the pc and start it after 10 minutes
it starts giving the start beep and works perfectly like a normal pc.

with regard plz. reply as soon as possible