hibernation

after using my windows vista home premium for some time the hibernation button disappeared and till now i can't get it back, though my windows is activated and vga configured, pls who can help.

All of these settings are configured in the control panel under "Power". These are default power modes and you can create your own power plan.

There is a ton of options at least for windows 7 so I assume this is true for vista .

in the command prompt please type the following command and you will have the hibernate feature back

powercfg -h ON

What is the difference between hibernate and sleep? And also I was wondering I was having issues with shutting down my laptop last night because I clicked shut down and it restarted it. I looked for settings and all I could find was on the control panel what actions I wanted for which button to click and they were all right. Then I was all confused about sleep and hibernate so I'm wondering about all that. Thanks for the help!
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market samurai ~ marketsamurai ~ marketsamurai.com

Sleep saves the current state in Ram and shutsdown pretty much every piece of hardware it can. This of course still draws some power because ram has to be powered.

Hibernate saves the state to the hard drive and consumes no power. I assume hibernate take more time to start backup because a hd is slower than ram.