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

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 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.

Removing XP from Vista Dual-Boot System

Restart your computer with either vista cd1 or dvd in driver. if once you in setup, choose repair console from the first screen.
Now the last option is for dos prompt, pick that
A DOS PROMPT appear , and type the following command:

bootrec.exe /fixmbr (Hit Enter)
this will essentially remove xp from the vista loader.