回答先: Will not see the USB portsiMac 21.5" Mid 2011 Ram 8GB: My display does not work. Then connected to external display still no display. Then I disconnected LCD and now display turned on. If I connect LCD then no display on LCD and External monitor. Now the iMac started and able to goto installation screen. HDD not recognized. As per the info on a forum disconnected HDD cables and connected again while system was running. Then HDD recognized and installed Lion. Rebooted few times looks everything fine. One of the application says wrong date and time. Then tried to correct it but I was not able to. Then I restarted iMac then HDD was not recognized. Tried the same way disconnect and connect the cables from HDD while system running. Still No HDD Then I tried SMC reset and trying PRAM but system is not taking the keyboard commands, I think Now when I start the system then it chimes and run for 4 minutes and suddenly restarts for 3 or 4 times and then goto off mode. Please help me. Thanks in advance.