Upgrade an Win2k3 EE evaluation to full license

Hello,

We’ve been running an evaluation copy of Windows 2003 Server Enterprise Edition and have now purchased a full license of it. I’ve been told that you just need to enter the new license key and it will be upgraded.

Can enyone tell me if this is true and if so how do I do it?

If not, do I just do an upgrade and hope that nothing gets corrupted etc?

Any help/advice would be greatly appreciated.