1. Make sure you have a working Windows installation disk.
2. Create your backup plan (Control Panel/System and Security/Backup your computer). Make sure you create a system image as well. Make sure you do not backup the temporary folders (they tend to occupy a lot of space).
3. Schedule your backup. If possible, schedule it to wake your computer, execute and then put your computer back to sleep.
B. Restore the system
1. If your system drive is still working, execute a manual backup.
2. Replace your drive.
3. Boot from your Windows installation disk or from your system repair disk.
4. In the setup menu, select “Repair your computer” and then follow the instructions.