When you shift + right click in Vista (or Server 2008) you will not find the trusted Run As ... Item, all you find is Run as Administrator. But this is not always what you need.
You can use the command prompt and the Runas command but this is not so easy as the old right click command.
Enter Sysinternals, they release a little tool called ShellRunAs that you can find here
After you downloaded it copy the ShellRunas executable to the windows\system32 folder and run shellrunas /reg
From this moment the run as different user item is back in your rightclick menu (or in your shift right click menu)
Thanks Sysinternals!
