Well, I have been recently asked another fundamental question about Windows - What is the difference between Standby and Hibernate?  You probably already know that both are designed as an energy conservation activity in your computer, but what is the difference between the two?  Here's a simple explanation:

Standby (Think 'Nap'):
When your computer goes into Standby, it will turn-off the power to all devices directly connected to your computer (your hard drive, modem, monitor, etc), but keeps power to your computer's memory.  This allows it to conserve power but to quickly come back when you press the power button.

Hibernate (Think 'Deep Sleep'):
When your computer goes into Hibernate, it will 'take a picture' of all the programs and files you currently have open, save it to a special part of your hard drive, then shut down the power to all parts of the computer.  When you press the power button to wake it up, it will restore power to all parts of the computer then restore your screen according to the programs and files you had open.

You can adjust how and how long it takes for either of these energy saving activities to start in the Power Management section of the Control Panel.

In Windows XP:
1. Start (button) > Control Panel > Power Options
To Customize Standby:
-In the Power Schemes tab
-In the Power schemes field:
2. Select a power scheme profile from the drop-down list
Alternatively, you can:
2. Setup your own power scheme by adjusting the times in the Plugged in and Running on Batteries (if you are using a laptop) profiles.  This might be helpful if you want your laptop to stay on longer before going into Standby
To Customize Hibernate
3. Click on the Advanced tab
4. Select how you want Hibernate to turn-on from the drop-down lists
5. Click Apply
6. Click OK

In Vista - Standby and Hibernate have been combined
1. Start (button) > Control Panel > Power Options
2. Choose one of the three Power Plans (Balanced, Power Saver, or High Performance)
3. Exit the window
-Your power plan is saved

That's it!