I'm trying to install Windows 10 Technical Preview on Microsoft Virutal PC 2007 SP1.
When I start it up to the windows logo for the restart it says:
Microsoft Virtual PC 2007 cannot run Windows 10, as the virtual/emulated hardware doesn't supply what's needed by Windows 8 and above.
Instead, try another VM software package that supports Windows 8+ (like VirtualBox).
For more information, check out this other SU question: Is it possible to install Windows 8 using Microsoft Virtual PC?