Restore Win Registry if windows is not booting

OK
I have to say that sometimes I need win Xp and this is why I keep on messing with it.
Today I installed my Bamboo tablet on win and BOOM ! Blue screen of death even if booting in safe mode.
So I tried to recover a previous configuration snapshot in the following way:

Boot a Bart PE cd *** (it's a live window system, but even a recovery console is ok, unfortunately I had no bootable Win CD since my laptop is a Dell and they only provide a recovery system cd which will reset your system)
From BartPE using file manager navigate to a snapshot folder from the right time frame - like
C:\System Volume Information\_restore{DBA0BBCB-A3EA-4494-AB37-23CB0DE9E357}\RP138\snapshot
There should be (among others)

_REGISTRY_MACHINE_SAM
_REGISTRY_MACHINE_SECURITY
_REGISTRY_MACHINE_SOFTWARE
_REGISTRY_MACHINE_SYSTEM

in there.

Copy these 4 files to \windows\system32\config folder.

In that folder rename the files, SAM,SECURITY,SOFTWARE and SYSTEM (Ieg, append .BAK). Then rename those 4 files you copied, removing the _REGISTRY_MACHINE_ prefix (so they replace the 4 you've just renamed .bak). Then reboot, and see if you have any improvement.

***note I tried to do that from linux which is already installed in my lap but I had no success writing in the windows config directory (it's a NTFS partition but I cannot figure out why I cannot write over there)