|Go one step farther. Turn it off completely when not in use.|
Check apm or acpi settings if available.
Be sure to press the space key to try to get monitor to come back on. Might take a minute or so to wake.
See event viewer logs.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10