Understanding The Registry Part 7

In this post we are going to deal with the hidden files of registry for different operating systems.

Windows 95: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:
[list=1]
* 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:

cd c:\windows

* 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.

If 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 C:\WINDOWS\SYSTEM.DAT.

Windows NT:On Windows NT you can use either the "Last Known Good" option or RDISK to restore to registry to a stable working configuration.

Clean out old data from the Registry:Although 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.