Need 32bit SSRS on 64bit chip

I'm confused on some things...
See http://technet.microsoft.com/en-us/library/ms143293(v=sql.90).aspx
So, I'm attempting to install SQL Express 2005 on my 64bit Win7 Ultimate laptop.  When installing SQL Express I get the message: ASP.NET Version Registration Requirement.  64-bit ASP.Net is registered.  Required 32-bit ASP.Net to install Microsoft Reporting Services (32-bit).
How can I easily unregister the 64bit ASP.Net and register the 32-bit (if the 32-bit is already installed!)  Is this registration process the only thing I need to do?
Guidance?
THANKS!