Windows NT is only as reliable as the hardware that runs it. In times of trouble, you'll be glad you have a backup, not just of important data files, but of system settings such as those in the Windows NT Registry.

Unfortunately, you can't save the entire NT Registry by backing up a few files, since some hardware-related settings are created every time you start NT. Still, you can and should make backups of other NT portions regularly or any time your system changes (for example, when you install new software). Here are some ways to do just that.

Winner tapes all. If your PC contains a tape drive, use NT's Backup utility to take a snapshot of Registry settings when it backs up other files. Choose StartûProgramsûAdministrative Tools (Common)ûBackup. Double-click the drive you want to back up, and then check the boxes for the folders or files you want to include. When you're ready, click the Backup button. Check the Backup Local Registry box, type a Description, and click OK. You must back up at least one file on the same drive as NT; otherwise, the Backup Local Registry box will be greyed out.

Caption: NT's Backup utility lets you include the Registry on a tape backup

Repair for tomorrow. When you installed Windows NT, it asked you whether you wanted to make an emergency repair disk, a resource that can come in very handy if you ever need to run Setup with the Repair option. Even if you chose Yes, you should keep your repair information up-to-date. NT's Repair Disk Utility ù though not as thorough as the Backup utility, which copies any files you want to a tape ù saves a compressed copy of Registry files in NT's Repair folder and on a floppy disk (if you so specify).

Select StartûRun, type rdisk, and press <Enter>. If you simply want to copy settings to a floppy, click Create Repair Disk. If you want to copy the files to the Repair folder on your hard disk, click Update Repair Info. The latter button makes a copy on your hard drive, then invites you to copy the same files to a floppy disk. If you want Repair Disk to include security account manager (.sam) and security database files, type rdisk /s- in the Run dialogue box. Repair Disk will update information in the Repair folder and then exit. If you type rdisk /s (without the hyphen), you'll also receive a prompt to make a floppy copy.

The /s and /s- switches overwrite the Registry .sam and security settings that were saved during installation. And because the .sam and security files saved with these switches contain information about all users and groups, the resulting backups are often too big for a floppy disk. Therefore, use the /s switch with caution.

Give it the boot. To copy Registry files manually, you must boot to another operating system (use a bootable floppy if necessary). Navigate to the folder where you installed NT and then to the Config folder in the System32 folder. Copy all files in the Config folder to a safe location. Unlike the backup files made with the Repair Disk Utility, these files won't be compressed. (Note: this procedure will only work if NT is installed on a FAT partition.)