How can you backup and restore the Registry?
Maintaining the Registry
included a utility on the Windows 95 CD-ROM that lets you create
backups of the Registry on your computer. The Microsoft Configuration
Backup program, CFGBACK.EXE, can be found in the \Other\Misc\Cfgback
directory on the Windows 95 CD-ROM. This utility lets you create up to
nine different backup copies of the Registry, which it stores, with the
extension RBK, in your \Windows directory. If your system is set up for
multiple users, CFGBACK.EXE won't back up the USER.DAT file.
you have backed up your Registry, you can copy the RBK file onto a
floppy disk for safekeeping. However, to restore from a backup, the RBK
file must reside in the \Windows directory. Windows 95 stores the
backups in compressed form, which you can then restore only by using
the CFGBACK.EXE utility.
Microsoft Windows 98
automatically creates a backup copy of the registry every time Windows
starts, in addition to this you can manually create a backup using the
Registry Checker utility by running SCANREGW.EXE from Start | Run menu.
What to do if you get a Corrupted Registry
95, 98 and NT all have a simple registry backup mechanism that is quite
reliable, although you should never simply rely on it, remember to
always make a backup first!
In the Windows
directory there are several hidden files, four of these will be
SYSTEM.DAT & USER.DAT, your current registry, and SYSTEM.DA0 &
USER.DA0, a backup of your registry. Windows 9x has a nice reature in
that every time it appears to start successfully it will copy the
registry over these backup files, so just in case something goes wrong
can can restore it to a known good state. To restore the registry
follow these instruction:
* Click the Start button, and then click Shut Down.
* Click Restart The Computer In MS-DOS Mode, then click Yes.
* Change to your Windows directory. For example, if your Windows directory is c:\windows, you would type the following:
* Type the following commands, pressing ENTER after each one. (Note that SYSTEM.DA0 and USER.DA0 contain the number zero.)
attrib -h -r -s system.dat
attrib -h -r -s system.da0
copy system.da0 system.dat
attrib -h -r -s user.dat
attrib -h -r -s user.da0
copy user.da0 user.dat
* Restart your computer.
Following this procedure will restore your registry to its state when you last successfully started your computer.
all else fails, there is a file on your hard disk named SYSTEM.1ST that
was created when Windows 95 was first successfully installed. If
necessary you could also change the file attributes of this file from
read-only and hidden to archive to copy the file to
On Windows NT you can use either the "Last Known Good" option or RDISK to restore to registry to a stable working configuration.
How can I clean out old data from the Registry?
it's possible to manually go through the Registry and delete unwanted
entries, Microsoft provides a tool to automate the process, the program
is called RegClean. RegClean analyzes Windows Registry keys stored in a
common location in the Windows Registry. It finds keys that contain
erroneous values, it removes them from the Windows Registry after
having recording those entries in the Undo.Reg file.