My monitor will only say power saving mode

[DeathlyIllXeno]

So I changed my power supply and when I put everything back together and connected the cords to the back of the computer I pressed the button to turn my monitor on and all it will say is "power saving mode" before it goes to sleep and I don't know what's wrong I've taken it my computer apart several times to try resolving this problem and nothing works, help would be deeply appreciate

Cavern

 

[Bo Lee]

Does your monitor have a source select? If so, try cycling it. Also, does your PC have more than one monitor jack? If so, try switching to another jack. The primary monitor jack could have gotten switched somehow.