Tech Tip: Back up the files that hold the registry

The Windows 9x registry actually consists of two files: System.dat and User.dat. These files offer another effective method for backing up the registry. You must, however, boot to DOS mode to do this—remember that while Windows runs, the files will be in use.

To do so, select the Restart The Computer In DOS Mode option from the Shutdown command on the Start menu. At the DOS prompt, ensure that you're in the system root (usually C:\Windows). Then enter the following:

attrib system.dat -s -h -r
attrib user.dat -s -h -r
copy system.dat c:\backup\system.dat [or another safe location]
copy user.dat c:\backup\user.dat
attrib system.dat +s +h +r
attrib user.dat +s +h +r

If your computer's registry now becomes completely corrupted, you'll be able to copy these files back into place using the reverse of the commands above. Enter the following:

attrib c:\windows\system.dat -s -h -r
attrib c:\windows\user.dat -s -h -r
copy c:\backup\system.dat c:\windows\system.dat
copy c:\backup\user.dat c:\windows\user.dat
attrib c:\windows\system.dat +s +h +r
attrib c:\windows\user.dat +s +h +r

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