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When you press power, can you hear the fans inside the machine turn on? Do you see any lights blinking?
If you press the button on the cd drive does it blink and open showing it has power?
Ok, Do you have a video card installed in the desktop tower?
or are you using the built in video on the motherboard?
And what type of cable connection goes from your monitor to the desktop.. VGA, HDMI, DVI, etc?
You may need to open the machine and see if a video card was installed..
Also, it would be worth removing the ram chips and reinserting them.. They could have slipped or been bumped loose when you removed the machine.
Also, if your monitor has a remote or settings menu, its worth cycling through the input options to see if maybe the monitor is on the wrong input options.
If you look at this video at about the 2 minute mark, youll see a card going sideways, that has VGA and HDMI and DVI connections on the metal end. T hats a video card
Definitely check to see if you have one as the card may have slipped loose and needs to be removed and reinstalled.
What you see as a useless waste of time and money, is the same process of elimination that the geek squad is going to go through when you see them.
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