plug it in press power it gives message on screen saying " PC MODE DISPLAY GOING TO SLEEP " T

[Rey78213]

plug in power on screen displays message " PC MODE " DISPLAY GOING TO SLEEP" THEN NOTHING if I push one of the 3 buttons left of the power on button it changes from pc mode to monitor mode please help 

[itsmyname]

It seems that the screen is not receiving any video signals from the motherboard, and so it goes to "sleep".

Does your All-In-One have a HDMI-input port, so that it can be connected to a stand-alone DVD player, or connected to a DVR/PVR (Digital Video Recorder/Personal Video Recorder) so that it can be used as a TV screen type of "monitor" ?

Is your HP Warranty still valid?

If not, then the nearest authorized HP Service Center will, for a fee, repair your computer.

[Rey78213]

Yes it does have hdmi port by plugging something into it is the only way to turn on computer