Thanks for answering but I know exactly what I want to do in the registry: manually integrate the Promise Fastrack (yes, declared as scsi mass storage) raid controller driver where it should be, as PnpEnum, pci device number, manufacturer's string id, etc. so that the OS takes it when booting, which is not the case at the moment (error message points at the OS not seeing the boot disk).
Microsoft's knowledge base has an answer about the error and gives good hints for solving the problem from within W2K.
What I am basically looking for is an utility or a trick which would allow me to open, edit and save the W2K config files from outside W2K.
I could easily solve the problem by un-ghosting the original saved partition, to a drive on the regular #0 ide channel 1, launch W2K, install the drivers, re-ghost the partition, un-ghost again to the raid array.
But I want to do it the dirty way for the fun of it, ie rip open the registry from outside W2K and put my hands in it

This would be very useful in many situations to restore a screwed install or to make changes or some tidying.
The sig tells about the original config (before adding a pair of 40 Gigs HDs on the raid controller) but this will not help.