Change Server 2003 Standard OEM key to Retail?

I had recently experienced a complete failure of our domain server. The Server was running on an OLD Dell hardware set with a Dell OEM MS Server Standard OS and KEY. Following the failure, and about 24 hours of struggling with our restore, we had no choice but to restore the system over a different server running server 2003 standard retail. Following the restore, a repair reinstall of the OS was required using the OEM cds (since the restored OS was OEM - trust me I tried everything to avoid this). Following this install we could no longer login to the OS without first activating the OS. The only way to do this, without the LAN driver installed, was to do it over the phone with MS, and, the only key MS would activate for that installed version of the OS was the original OEM Dell key from the old server. Now we have an OEM install running on a server that is licensed for retail. In order to remain legal, I need to change this OEM key to the correct Retail key without blowing the OS to garbage. How do I do this? We will have backups and a secondary DC running but I still don't want to pull another all nighter just yet. ThanksChange Server 2003 Standard OEM key to Retail?
Try this piece of open source software. It will find the key installed and under options allows you to change it. http://magicaljellybean.com/keyfinder/