Thanks. So reg tweaks are the only changes made, right ?
I was booting Portable 7 in AHCI mode. It works OK when the default (MS) AHCI drivers are used. If I update the AHCI drivers with the latest Intel AHCI driver, I get a blue screen on boot ( IRQL_LESS_THAN ... ).
This does not happen with the source Win 7. I assumed it was because of some change made by VHD_W7_Compact.
I made Portable 7 (in AHCI mode) from a source without Intel AHCI drivers & from a source with Intel AHCI drivers. Same prob.
Not really important. I'm going to use IDE mode only from now on.