Q I have a Dell Inspiron 6400 computer running Windows Vista. The option to make it hibernate has disappeared.
I have been into the Device Manager to check whether the PC is using ACPI power management and it shows that it is.
I am quite sure the option to hibernate was there before, but now I can’t find it. I have been into the computer’s Bios, but there is no obvious option to switch hibernation on or off.
Misheck
A Hibernate is a useful feature for notebook users, although it is one that seems to appear and disappear for all sorts of strange reasons.
The first place to look is in the Device Manager but as you’ve said, your ACPI settings are correct.
One thing to note is that the Hibernate option may not appear if you don’t have sufficient space on the hard disk to store all the hibernated files – when the computer goes into hibernation, it copies its entire state, including all running programs, open files and everything that’s in its memory, to the hard disk, then cuts the power.
Therefore, it might be worth making sure that there’s more space on your hard disk than you have memory installed on the computer – for instance, if you have 2GB of memory installed, then you might need something like 10GB of free hard disk space to be on the safe side.
If that’s not the problem, make sure the PC isn’t in Hybrid Sleep mode. This is new in Windows Vista and is, as the name suggests, a combination of hibernation and the standard sleep mode. When it’s enabled, you’ll only see the Sleep option in the Shutdown menu.
You can switch Hybrid Sleep off in the Power Options control panel. Click on Start, then Control Panel, System and Maintenance, Power Options. Next, click on ‘Select a power plan’ and then ‘Change plan settings’.
