Restore the System State portion of the backup on another machine running W2K3 or Windows XP, choosing the "Single Folder" option for the "Restore files to" and picking some sensible "Alternate location" (like a directory you make for that purpose). You'll be warned about how this is an "advanced" feature and that not all files will be restore. For your purposes, that's fine.
You'll get back a lot of the "%SystemRoot%\System32" directory (a lot of DLL files, etc), and the registry, too.
From there, the instructions that Shial (who seems to look rather like SHODAN) posted are the right track. Fire up "REGEDIT", highlight "HKEY_LOCAL_MACHINE" in your local registry, then use the "File / Load hive..." option. Choose the file from the "Alternate location" corresponding to the part of the registry you want to extract data out of (these files have no extension):
- SYSTEM - HKEY_LOCAL_MACHINE\System
- SOFTWARE - HKEY_LOCAL_MACHINE\Software
- SECURITY - HKEY_LOCAL_MACHINE\Security
- SAM - HKEY_LOCAL_MACHINE\SAM
- DEFAULT - HKEY_USERS.Default
Choose any name you want when loading the hive, so long as it isn't a name that's already used under HKEY_LOCAL_MACHINE. You're "mounting" that hive into your live registry, not unlike mounting an NTFS volume under a directory (except that you don't have to make the registry key to mount the hive into like you would an NTFS mount point).
When you're done, unload the hive by highlighting the key where it's mounted (HKEY_LOCAL_MACHINE\whatever_name_you_chose) and doing a "File / Unload hive...".
Best Answer
The system state contains a number of items:
Some of these items are only included if the specified service is installed (AD, IIS, Certificates). (Details are online. TechNet: Server 2003/2003R2. MSDN: Server 2003/2003R2.TechNet forums: Server 2008. MSDN: Server 2008 and upwards)
If you need to restore a server, you will need this state to recover the registry, or your AD Domain, or IIS sites.
You can restore system state to the same server, or another server with identical hardware. Microsoft does not support restoring system state to different hardware (see this article), however it is possible in some occasions, and with some parts of the system state, for example the IIS metabase. In that guess its really a case of try it an see, but its not a recommended solution..