Restart windows without restarting your pc

this works both with windows vista and xp.so hers the trick..
Windows vista :
Select Start, then hover over the right arrow that is to the right ofthe padlock icon until the pop-up menu appears that contains “restart”as one of it’s choices. Hold down the SHIFT key while clicking on the“restart” choice.

Windows xp : Select Start. Select “Shut Down…”. Change the drop-down combo box under “What do you want the computer to do?” to “Restart”. Hold down the SHIFT key while clicking on the “OK” button.