Standby mode doesn't work

Helpline Q&A Directory

My computer has a problem with the Standby function of the Shutdown menu: it only seems to work if the computer has been on for less than 15 minutes. If it has been on for longer than that, the computer comes back on immediately. No one seems able to suggest a solution. Can you help?

The Standby function puts the computer to sleep in order to save power, so it is really intended for use with laptops. The computer will be woken up when an external signal occurs. This is usually a key press or a mouse movement, but it could be an interrupt from a device such as a modem (in case you are using fax) or voicemail software that needs to be able to respond.

To check the setting of the Standby function, enter the Bios setup menu, go into the Power Management settings and check to see if any of the settings currently selected could be causing the computer to wake up when you don't expect it to.

It's quite likely that vibration or tension in the cable could be moving your mouse, causing the computer to wake up. This certainly happens with one of our PCs, causing it to wake up any time from straight away to a few minutes after it was put into standby. The only solution we have found is to turn the mouse upside down (so that no movements can be transmitted to the roller ball) and then select Standby using the keyboard.

The fact that the problem seems to occur only when the computer has been on for 15 minutes or more may be just a coincidence. But there's a faint chance that the mouse electronics, or even the controller on the computer motherboard, when warmed up, are generating spurious interrupts.

You could test the first possibility by substituting a different mouse, but there's no easy way to check the second. Even if that is the culprit, though, it probably isn't worth the cost of a new motherboard just to solve this minor problem.