HDMI when plugged into PC only displays desktop background

[Harryc1996]

When I post my HDMI cable into the hdmi port in the centre of my PC to my , the only aspect of my PC displayed will be my desktop background, no cursor, desktop icons, windows bar at the bottom of the screen, if I press CTRL+ALT+DELETE then the display will be black and won't even show my desktop background.
Also when I play games (pretty much any game) I will get a jiterring line across the top quarter region of my screen, this is more or less when I move in game etc. know any solutions to this, too?

Thanks so much for reading this, been putting up with this for about a year now and it's been really frustrating. To note: every aspect of my PC is perfectly functional and works fine, also the cable is brand new and works fine.

 

[popatim]

From your description I beleive you have multimonitor mode enabled but only 1 display is connected, the extended display.
Assuming you have a graphics card you installed yourself:
Enter your bios and see if you can disable your integrated GPU or set the GPU To initialize first to PEG, PCIE, or add-in card.