$ 0 0 F11 immediately after powering on. Windows 7 Recovery: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01867418&cc=us&dlc=en&lc=en&jumpid=reg_r1002_usen_c-001_title_r0002 Windows 8 Recovery: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c03489643&tmp_task=solveCategory&cc=us&dlc=en&lc=en&product=5336700#N144