In one of upgrade project from SharePoint 2007 to SharePoint 2013, first step for me was to refactoring the existing MOSS VS solution to SharePoint 2010 Visual studio project.
Doh, I need MOSS and SharePoint 2010 in same machine to make this refactoring easily.
I don’t wanted to do upgrade from 2007 to 2010, but needed both on single machine. Time for reflection.. 🙂
After little digging out in psconfig.exe in reflector found one interesting thing
It was checking following registry path
“Software\\Microsoft\\Shared Tools\\Web Server Extensions\\12.0\\WSS\\InstalledProducts”
Looking at logic, I just renamed folder “12.0” to “12Old”. Well temporarily.
Started the SP 2010 setup again.. and VOILA.. Setup started behaving there is no SharePoint installed on my machine. Everything went like blank install on new machine. After central admin wizard, I just renamed the “12Old” back to “12.0” in registry. Manually I was required to restart all MOSS 2007 services from Services. Reboot the machine and done.. You will see MOSS and SP2010 on single machine running perfect.
There were some hickups in using.. many random unexpected errors were coming, but it was fine as developer box.
Best luck if you are also going to do this..