Although this is not a supported scenario, there is a way to install MOSS 2007 onto Windows 7 Release Candidate (build 7100). Here are the steps:

• Get the Installation Helper, created by Bamboo Nation.
• Get the MOSS 2007 installation media and extract it to a temporary folder on your hard drive
• Get the MOSS 2007 SP2 service pack: http://www.microsoft.com/downloads/details.aspx?FamilyId=B7816D90-5FC6-4347-89B0-A80DEB27A082&displaylang=en
• Get the WSS 3.0 SP2 service pack: http://www.microsoft.com/downloads/details.aspx?FamilyId=79BADA82-C13F-44C1-BDC1-D0447337051B&displaylang=en

Now you need to slipstream the installation packages (if you try to run the installer without SP2 slipstreamed, you will be blocked (KB 962935)

http://blogs.msdn.com/opal/archive/2009/05/08/install-moss-2007-wss-3-0-on-windows-server-2008-r2-you-will-need-sp2-slipstream.aspx

To create the slipstream package, follow the steps in http://technet.microsoft.com/en-us/library/cc261890.aspx. Basically, you need to open a command prompt and execute the following commands:

• wssv3sp2-kb953338-x64-fullfile-en-us.exe /extract:C:\TEMP\MOSS2007x64\Updates
• officeserver2007sp2-kb953334-x64-fullfile-en-us.exe /extract:C:\TEMP\MOSS2007x64\Updates

Delete Wsssetup.dll because it may conflict with Svrsetup.dll. Having both Wsssetup.dll and Svrsetup.dll in the updates folder for a slipstreamed installation source is not supported.

Run the SetupLauncher from C:\Program Files (x86)\WssOnVista\Setup

Locate the setup.exe in your installation folder.