Prevent Windows Update Reboots
Your PC doesn’t have to reboot, even if it installs an update.
MANY PEOPLE LEAVE THEIR PCs ON all of the time. That often means dozens of open windows, and information that hasn’t been saved as recently as possible. There’s nothing worse than going back to your PC and seeing a message that says “Windows recently downloaded and installed an important security update to help protect your computer. This update required an automatic restart.” Or, while you are working, you may grow tired of the nagging little pop-up window with a countdown that tries to reboot your computer in 15 seconds. A simple edit to the system Registry will end this annoyance and save you from losing potentially hours of work if a reboot occurs when you aren’t there to prevent it.
In fact, the U.K. publication The Register recently reported that a computer consultant in the U.K. has invoiced Bill Gates for £1,200 for “sabotaging” his work, left open during a critical system update reboot. Even if you tell Windows Update that you wish to perform a custom manual installation of new software, updates can still be pushed down to your system. Most of these critical updates are system-level files that require a reboot to fix problems properly, but you can still make Windows work the way you want it to.
Click Start, then Run. Then type regedit and press Enter. Be careful in the Registry, following the directions slowly and reading twice before clicking once. With the Registry Editor opened, click and expand HKEY_LOCAL_MACHINE\SOFTWARE\ Policies and finally Microsoft\Windows. Rightclick on Windows and select New\Key with your left mouse. Type WindowsUpdate and press Enter. This will create a new folder.
Now right-click on that folder and create another new key, this one named AU, and press Enter. AU stands for Auto Update. Turn to the right-hand pane, where an entry reads (Default); right-click on the white space and select New DWORD Value. Enter the string NoAutoRebootWithLoggedOnUsers, and press Enter. Now double-click that entry and change the Value Data to a 1, with the Base button of Hexadecimal selected.
Click on File | Exit, after which the Registry autosaves (just as other applications ought to but don’t), and reboot. Once Windows loads this value it should never force a reboot when you are not present. It’s a small price to pay for regaining control of your computer.
Source: PC Magazine Nov 7, 2006