The monitor screen blanks after it is idle for some time even without the screensaver
Cause: This could be due to the Power Management settings in either Windows or the BIOS. The settings control when the monitor should blank out after a period of inactivity.
Solution: Disable Power Management (ACPI) in the BIOS. If required, disable it in Windows as well. (Right-click on the Desktop, select Properties, and click the Power Management button on the Screen Saver tab).