Hello, to do a cold reset on this machine you will need to go into the pre-boot menu.
1. Turn the product on.
2. The HP logo displays on the product control panel. When a "1/8" with an underscore displays
below the HP logo, touch the logo to open the Preboot menu.
3. Use the down arrow button to highlight Administrator, and then touch the OK button.
4. Use the down arrow button to highlight Startup Options item, and then touch the OK button.
5. Use the down arrow button to highlight the Cold Reset item, and then touch the OK button.
6. Touch the home button to highlight Continue, and then touch the OK button.
Service pin: 05057512
Hope this helps....