What happens exactly? The montitor does not reboot, the computer does. Are you saying when you turn off your computer it won't turn on for 10 minutes, or the monitor won't turn on for 10 minutes after you turn it off? Are you just saying it takes 10 minutes for the computer to reboot back to Windows?
Have you tried a different monitor? If you are saying the computer seems slow to reboot, what are your system specs? Have you run a spyware and virus check? When was the last time Windows was re-installed?