In the past I have set the Windows XP Power Options to turn off the monitor (i.e. put the monitor into power saving/standby mode) after 1 hour of inactivity. However, this setting no longer works. I have tried a few different time periods, and found that setting the turn off time to 1 or 2 minutes works, but it does not work for longer periods.

Quite a few people have reported the Windows screen saver can interfere with the power saving settings. It is possible the screen saver makes Windows believe there is still activity on the monitor and therefore will not power down after the 1 hour period of (seeming) inactivity. This could also explain why the problem does not occur when setting the power options to a very short time period (e.g. 1 or 2 minutes) because this triggers the monitor to power-off before the screen saver kicks-in. We should try disabling the screen saver to see whether the screen saver is actually the cause of the problem. Go to the ‘Start’ menu > ‘Control Panel’ and open the ‘Display’ control panel (you may need to first click ‘Appearances and Themes’ if the Control Panel is being displayed in Category view). In the window that appears, click the ‘Screen Saver’ tab. From the Screen Saver selection box, select ‘(None)’ and click OK. Now, go back into the Power Options and set the monitor to power-off after 1 hour (or, if you like, a shorter time period such as 30 minutes). If the monitor turns-off after that time period, the screen saver is the problem. However, the problem may not be due to screen savers in general, but may be caused by a specific screen saver (there have been reports of the problem being caused in particular by the Windows 3D screen savers). In any case, try changing to a different screen saver, such as one of the standard Windows screen savers to see if the problem persists.

In the unlikely event that the screen saver is not the problem, you could try downloading the latest drivers for your monitor from the manufacturer’s website. While most monitors will work fine with the default Windows monitor driver of (Plug and Play Monitor) you may miss additional functionality for your monitor by not installing the drivers. Not all monitor manufacturers release drivers for their monitors, but it is still worthwhile having a look.