From this page at M$. Q. Will the settings I created when using the Evaluation Kit software remain in effect after the 180-day trial, when I install the retail version? A. Yes. If you select the Upgrade option when prompted during setup of the full version (that is, non-evaluation) product, your settings will remain intact. Q. If I have Windows Server 2003 Release Candidate 1 (RC1) or Release Candidate 2 (RC2) and I want to upgrade to the final RTM version, will this be possible? A. Yes. You may upgrade from RC1 or RC2 to the RTM version. Q. I recently installed the 180-day trial version of Windows Server 2003. When I buy the full version of this software, will I have to install it over the evaluation copy? A. Yes. After the 180-day trial period, you will have to install the full version (that is, non-evaluation) product. Q. Can I use the Product Key that is included when I buy a copy of the full version (that is, non-evaluation) product to remove the 180-day limit instead of installing the full version product? A. No. You must install the full version of the product. The new Product Key will not override the 180-day limit on the evaluation software. When you install the full version product, select the Upgrade option when prompted during setup. This will keep the settings you established when you installed the evaluation version of the software. Dont know if this helps but seems as though the RC's will expire themselves and their keys won't work with the Final release. Hope this helped --Likuidkewl