WIN98 and ME users. The registry is automatically backed up, no need to install ERUNT, check HERE for how to restore a copy of the registry.
Note that this Tech Tip also applies to the 32 and 64 bit versions of Vista and Windows 7.
ERUNT (Emergency Recovery Utility NT) allows you to keep a complete backup of your registry and restore it when needed. The standard registry backup options that come with Windows backs up most of the registry but not all of it. ERUNT however creates a complete backup set, including the Security hive and user related sections. ERUNT is easy to use and since it creates a full backup, there are no options or choices other than to select the location of the backup files. The backup set includes a small executable that will launch the registry restore if needed.
Download ERUNT from the following locations: http://www.larsheder...nline.de/erunt/
The file you will download is erunt-setup.exe. Use any of the servers, 1, 2 or 3.
Please read the Detailed Information link on the ERUNT site or the Documentation that is available from the ERUNT folder after you install it.
Here's an excellent ERUNT Installation Tutorial, with pictures on GeeksToGo.com. Vista and Windows 7 are slightly different and may require you to allow the installation via User Account Control (UAC).
NTREGOPT is also installed when ERUNT is installed.
NTREGOPT works by recreating each registry hive "from scratch", thus removing any slack space that may be left from previously modified or deleted keys. In other words, it compacts the Registry to a smaller size which allows Windows to load & perform a little faster sometimes.
Note that the program does NOT change the contents of the registry in any way, nor does it physically defrag the registry files on the drive (as the PageDefrag program from SysInternals does). The optimization done by NTREGOPT is simply compacting the registry hives to the minimum size possible.
If you have ERUNT installed and doing regular backups of your registry each time you boot, then recovery from registry related problems is easy. See the information in the ERUNT Documentation under Restoring the registry with ERDNT for details. It would be a good idea to print out all of the documentation or at the least the parts on the various methods of restoring the registry and keep it in a safe place. When you need it the most, it will be unavailable because your computer won't boot!
If you start ERUNT and do a manual backup, you will see that the default location for storing backups is C:\WINDOWS\ERDNT.
To restore, just navigate to that location then chose a restore that you named (manual backup) or open the Autobackup folder then choose the date you want to restore to, open that folder and double click on it's ERDNT.EXE file. Take all defaults and follow instructions. Reboot when done and the restored registry will be active.
Restoring the registry when your system won't boot is covered in the Documentation.
Note: Most of the above was taken from a post by MrCharlie. I just massaged it a bit and added some additional info (with his approval).
Edited by Ztruker, 30 April 2011 - 08:00 PM.