What do you have to do to get your computer monitor up and running? Another common issue is with the 2nd monitor detected but not displaying. There are so many reasons why this could have happened: you may have an ailing monitor, problems with your graphics card, or cable or wiring problems.Īll the more, this problem becomes very worrisome if you need to get things done. A computer that powers on but with no signal to the monitor can be a puzzling thing.