Windows 95
Microsoft included a service on the Windows 95 CD-ROM that lets you create backupes 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.
After 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.
Windows 98
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
Windows 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!
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:
1. Click the Start button, and then click Shut Down.
2. Click Restart The Computer In MS-DOS Mode, then click Yes.
3. Change to your Windows directory. For example, if your Windows directory is c:\windows, you would type the following:
cd c:\windows
4. Type the following commands, pressing ENTER after each one. (Note that SYSTEM.DA0 and USER.DA0 contain the number zero.)
atttrib -h -r -s system.dat
atttrib -h -r -s system.da0
copy system.da0 system.dat
atttrib -h -r -s user.dat
atttrib -h -r -s user.da0
copy user.da0 user.dat
source:
http://www.pctools.com/guides/article/id/1/page/5/
