You can load another windows hive right in Windows using regedit, no need to use a third party software.
Connect the drive to another Windows PC as secondary or use a usb adapter.
When in registry editor, highlight HKLM (or whichever hive you need to load), then do a File>load hive navigate to (drive letter):\WINDOWS\System32\config of the crippled drive and highlight the file "Software" (or navigate to another hive you need to load) hit ok, it will ask you to name the hive it is about to load, give it a unique name like Test, hit OK, it will load the hive under HKLM with the name Test, Make and changes you need then highlight "Test" and do File>Unload Hive. Be sure to have the Test key highlighted when you select unload.
I have never encountered problems using this method but thought I should post the "possible" risks see this article
Note WinXP has a new feature called Registry Repair and Recovery (MS KB Q815011) and it is usually activated when starting WinXP. But it is also activated when loading an offline hive, which can have the undesired effect that the loaded hive is modifying behind your back. One can disable this feature in WinXP SP1 in case one is afraid that the "Repair" feature will do more harm than good:
[HKEY_LOCAL_MACHINE\ System \CurrentControlSet \Control \Session Manager \Configuration Manager]
SelfHealingEnabled = 0
I have never done this using a W7 PC either, which has a more aggressive self healing mechanism. but seems to be related to the files system rather than the registry, one would assume it also has a self healing registry similar to XP.
Other offline registry editing tools.