Page 5 in your users manual : 6 settings you have 45 seconds to push exit button to save. I have had times that when changing computers that I have had to disconnect the video cable, power down the monitor and computer, power up the monitor with nothing connected to re-set it, power everything down, reconnect monitor, and restart the system. Most times the H191W will detect everything If you need a manual
www.envisiondisplay.com or 1-888-838-6388 can help you. I have used this monitor for several years and think its one of the best. The technical support should help you. Hope I helped.