My monitor will not come on, the on/off lig...

Typically on Dell Monitors you will have a amber light that shows the power is on,but there is no communication with the pc, then there is a green light that shows that the monitor is on and communicating with the computer, this is when you will see something on the monitor. If you have the amber light on and your pc is on at the same time, check the commutation between the monitor and the computer, you can check this by looking at the cable that is connected to the VGA port in the back, most of the time the color will be blue, try to check to see if the cables are loose. if everything is tight and plugged in, you might have a trouble VGA card or monitor. I hope this helps.

make sure that your cpu is working. if the cpu is dead, there will be no display in the monitor. If the monitor light is flashing as you said, it could be the CPU not sending video signal to the monitor. also check if the cpu beeps when you start your computer. if not, check your cpu. try to re-seat your RAM modules. this will solve most of these types of problems