Sounds like you have a power settings problem.
Check that you screen save is set as 'none' to cancel out screen saver:
check also power settings to suit your PC and power supply.
This may differ from Server, desktop, laptop configurations.
Using Power Options in Control Panel, you can reduce the power consumption
of any number of your computer devices or of your entire system. You do this
by choosing a power scheme, which is a collection of settings that manages
the power usage by your computer. You can create your own power schemes or
use the ones provided with Windows.
You can also adjust the individual settings in a power scheme. For example,
depending on your hardware, you can:
Turn off your monitor and hard disks automatically to save power.
Put the computer on standby when it is idle. While on standby, your entire
computer switches to a low-power state where devices, such as the monitor and
hard disks, turn off and your computer uses less power. When you want to use
the computer again, it comes out of standby quickly, and your desktop is
restored exactly as you left it. Standby is particularly useful for
conserving battery power in portable computers. Because Standby does not save
your desktop state to disk, a power failure while on Standby can cause you to
lose unsaved information.
Put your computer in hibernation. The hibernate feature saves everything in
memory on disk, turns off your monitor and hard disk, and then turns off your
computer. When you restart your computer, your desktop is restored exactly as
you left it. It takes longer to bring your computer out of hibernation than
out of standby.
Typically, you turn off your monitor or hard disk for a short period to
conserve power. If you plan to be away from your computer for a while, you
put your computer on standby, which puts your entire system in a low-power
state.
Put your computer in hibernation when you will be away from the computer for
an extended time or overnight. When you restart the computer, your desktop is
restored exactly as you left it.
To use Windows Power Options, you must have a computer that is set up by the
manufacturer to support these features. For more information, see the
documentation that came with your computer.
