When I initially set up the PC, it worked fine.  I exited and hit Sleep.  When I returned to PC a few days later, the computer was off, I powered it up, got the Acer name on monitor and then screen went gray.  Monitor, keyboard and mouse all functioning, computer was on but all I had was a gray screen.  Disconnected everything, re-connected it all and still had the gray screen.  Somewhere found advice to hit F2, 9 and 10 at once, release, hit Enter - it worked.  Two days later, the same gray screen and the F buttons did not work.  Found more advice to swap monitor from one HDMI port to another, that worked but in 45 minutes when I went back to PC, same gray screen.  Never had this issue with Gateway, Dell or HP.  Ready to take a sledge hammer to Acer.  A waste of over $400.