Upgrading Windows Server 2008
How can I remotely upgrade a server running Windows Web Server 2008 R2 to Windows Server 2008 R2? Do any remote access tools allow me to do this?
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What you'll be doing is "migrating," not upgrading. To accomplish this you should have some kind of remote access card or KVM set up. Of course, you will need to back up your current setup.
With that said, it's perfectly valid to do bare-metal installs remotely. Remote access cards are worth every penny.