How can I stop Windows 7 rebooting to install updates

I have the RC of Windows 7 and I have a lot of really important stuff pen on my pc, it says it installed new updates and it needs to reboot, it lets me post-pone the reboot by 10 min - up to 4 hours but that is it, not option to reboot when I want to, is there anyway at all to make it not reboot within the next 4 hours without manually clicking the buttons to keep extending it by 4 hours?

As Col said, stop the update service. This can also be done through the action center/ windows update method. Only check manually and when you can restart straight away.

3rd party method is this software. Does loads of stuff which may be useful but will "Disable automatic restart after Windows Updating". http://www.winvistaclub.com/Ultimate_Windows_Tweaker.html

Edit: It's also a portable app, no need to install.

Or you can avoid that problem altogether by disabling automatic updates and updating manually when you are ready.

Just select "Check for updates but let me choose whether to download and install them" in Control Panel/Windows Update. That way you will always know about new updates and (hopefully) won't forget to install them :]

Run -> gpedit.msc -> Computer Configuration -> Administrative Templates -> Windows Components -> Windows Update -> Re-prompt for restart with scheduled installations

Set to enable and 1440 minutes (24 hours) and reboot whenever you have time.