How to disable and re-enable hibernation on a computer that is running Windows

source: http://support.microsoft.com/kb/920730

Let me fix it myself

To make hibernation unavailable, follow these steps:

1. Click Start, and then type cmd in the Start Search box.
2. In the search results list, right-click Command Prompt, and then click Run as Administrator.
3. When you are prompted by User Account Control, click Continue.
4. At the command prompt, type powercfg.exe /hibernate off, and then press ENTER.
5. Type exit and then press ENTER to close the Command Prompt window.

To make hibernation available, follow these steps:

1. Click Start, and then type cmd in the Start Search box.
2. In the search results list, right-click Command Prompt, and then click Run as Administrator.
3. When you are prompted by User Account Control, click Continue.
4. At the command prompt, type powercfg.exe /hibernate on, and then press ENTER.
5. Type exit and then press ENTER to close the Command Prompt window.