How do I restore the Windows 7 operating system on the HP Z420 Workstation?

Windows 7 can be reinstalled using HP Recovery Manager by booting from disc 1 of the HP Recovery Manager set and following the prompts. Be aware that the HP Recovery Manager process deletes all information on the primary hard drive, including all partitions, so you must back up your data before proceeding. If you did not order Recovery Manager media with your workstation, you can call HP support to request an HP Recovery Manager media kit. (Page 27)