Windows Backup Registry

Back up your registry

Click "Start" and enter Regedit in "Run" to start Registry Editor. The use of Registry Editor is simple,
The right mouse button improves productivity, but it's important to remember that you must back up the registry before making any changes to the registry.
Otherwise, the system may not start because of some changes. The Windows Registry database is basically made up of SYSTEM.DAT and USER.DAT,
And Windows is backing up the registry to SYSTEM.DA0 and user.da0 each time it starts to improve its reliability against accidental damage.
If the system startup error, we can also enter the Windows directory under DOS, with the attrib command to change their system, implied, read-only properties,
Copy the. DA0 into the. dat.

Back up the registry under DOS

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But that's still not safe. It is best to back up these two files when Windows is running normally:
Enter the DOS environment first when the computer starts, and start with the following:
CD \ Windows
attrib–r–h–s system.dat
Attrib–r–h–s The User.dat
changes the properties of these two files to visible, non-system files so that the files are available for copying.
Copy system.dat system0.dat
copy user.dat user0.dat
System0.dat User0.dat These two files are the file names after the backup. In the future, no matter how bad your registry is,
just copy the two files back and it will be back to your backup status.
attrib +r +h +s system.dat
attrib +r +h +s user.dat
After the copy is complete, restore the properties of System.dat User.dat.