Windows 7 How to apply a *.reg script into the Registry of a dead/not running Win7 system? Read possible?

The scenario is as follows:

A Win7 system has some problems and could NOT be booted itself.

So I took an additional bootable repair or LiveSystem CD and start the computer with it.

I have now a running WinOS and another dead Win7 e,g, on a partition C: on a hard disc.

Now I want to apply an existing *.reg Script into the registry of the dead system (=NOT the currently running system.

Can I do this somehow?

Is there e.g. a command

regedit myscript.reg -writetowin C:\Windows

whch writes the *,reg file to the Registry of the Win7 system which it find on partition C: in folder "Windows"?

Maybe I can address the target registry file directly

regedit myscript.reg -writeregistrydirect C:\windows\ntxxxxxxx.dat

In which file(s) is the Registry stored?

Second question: Can I at least read from such an external dead Registry?

Peter