I don't know if folks are still having trouble with this, but I'll share my experience and how I got it to work.
Environment: Windows 7 64bit, IIS 7.5, had CF developer 9.02 installed.
After installing, answering to use CF 10 for sites, first problem was that it tried to go to CF admin/config using 127.0.0.1 for localhost. I'm on comcast with wifi, so my localhost is 192.168.0.104.
Changed url to localhost and got error about duplicate entry for hbmxmlHandler. This is in the webroot web.config file, in my case C:\inetpub\wwwroot\
When I looked at web.config, handlers were pointing to CF9 not CF10. Also, in IIS, the virtual directories for CFIDE, Jakarta, etc. were still CF9.
Strangely enough, the CF10 web server configuration tool only had "None" available for sites to configure on localhost!
To eliminate all the trial and error iterations that didn't work... here's what did:
1) Go to the ColdFusion9\runtime\bin folder and execute the wsconfig.exe (right click to run as administrator) to remove the ISS All. So, no CF9 site support on any sites.
2) Run the CF10 web server configuration tool to add ISS All. Do not check 32bit support if you're on 64bit, it won't work.
3) Alter the web.config (for every site) to delete the <handler> and <defaultdocument> sections.
My web.config looked like this:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<handlers>
<add name="JWildCardHandler" path="*" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\1\jrun_iis6_wild card.dll" resourceType="Unspecified" requireAccess="None" />
<add name="hbmxmlHandler" path="*.hbmxml" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="cfswfHandler" path="*.cfswf" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="cfrHandler" path="*.cfr" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="cfcHandler" path="*.cfc" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="cfmlHandler" path="*.cfml" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="cfmHandler" path="*.cfm" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="jwsHandler" path="*.jws" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
<add name="jspHandler" path="*.jsp" verb="*" modules="IsapiModule" scriptProcessor="C:\ColdFusion9\runtime\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
</handlers>
<defaultDocument>
<files>
<add value="index.cfm" />
</files>
</defaultDocument>
<staticContent>
<mimeMap fileExtension=".air" mimeType="application/vnd.adobe.air-application-installer-package zip" />
</staticContent>
</system.webServer>
</configuration>
After editing, it now looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<staticContent>
<mimeMap fileExtension=".air" mimeType="application/vnd.adobe.air-application-installer-package zip" />
</staticContent>
</system.webServer>
</configuration>
CF 10 is apparently using the isapi_redirect.dll for everything that used to be in the web.config.
** Also, please note that in CF 9, I had to change any sites not under default to use the defaultAppPool so they could inherit, as well as enabling ISAPI on the default site in handler mappings.
4) Run your localhost CFIDE/Administrator and it should come right up.
There may be a shortcut to all this, but it is what worked for me. Of course, now I've lost CF9.