This is from Kelly's Korner: Backup and Restore for Windows XP
Use Backup to Restore Files and Folders on Your Computer
Click Start , point to All Programs , point to Accessories , point to System Tools , and then click Backup . The Backup or Restore Wizard starts. Click Advanced Mode. Click the Restore and Manage Media tab. Use one of the following steps:
If you want to restore from a backup file, expand File, and then expand the backup file that you want. For example, expand Backup.bkf created 01/01/2002 at 1:15 PM . Backup includes the date and time of the backup as part of the file name by default.
If you want to restore from a tape backup, expand the tape device that you want (for example, Travan ), and then expand the media name that you want. For example, expand Media created 01/01/2002 1:15 PM .
Select the check boxes for the folders that you want to restore. If you want to be more specific in your selections, double-click the folder that you want, and then select the check boxes for the files or folders that you want to restore.
If you are restoring the entire operating system, select the System State check box.
NOTE: If you want to restore the operating system as well as your data files, you should restore the System State data, which includes such things as the registry, the COM+ class registration database, files under Windows File Protection, and boot files.
In the Restore files to box, use one of the following steps:
Click Original location if you want to restore the files to the location from which you backed them up. Use this selection when you restore the entire computer.
Click Alternate location if you want to restore a file or files to another location on the hard disk. Type the location that you want in the Alternate location box. Use this selection to prevent the restore operation from overwriting existing files on your computer.
Click Single folder if you want to restore a file or files to a single folder on the hard disk. Type the location that you want in the Alternate location box. Use this selection to separate the restored files or folders from the rest of the files on the hard disk. On the Tools menu, click Options.
Click the method that you want Backup to use when it restores a file that is already on the computer, and then click OK. Backup uses this selection to determine whether to overwrite an existing file only when it restores a file in a folder that contains the existing file. NOTE: If you are restoring the operating system, click Always replace the file on my computer. Click Start Restore. If the following message appears, click OK if you want to restore the System State information with the selected backup: Warning: Restoring System State will always overwrite current System State unless restoring to an alternate location.
In the Confirm Restore prompt that appears, click OK . A Restore Progress dialog box appears, and the restore operation starts. When the restore process is complete, click Close. If you are prompted to restart the computer, click Yes.