No signal to monitor?

Why does my computer monitor work sometimes and sometimes get no signal?

• When i turn my computer desktop on, it sometimes works and sometimes doesn't. When the monitor gets signal, i can play on the computer as long as i want without a problem. But only when i switch the computer off and try to turn it back on the monitor says "no signal" and the light goes from blue (working) to orange (no signal). When it gets a signal it works perfectly but when u turn it on and it doesn't, it's a nightmare. My Computer Specs are CPU: Intel E6750 GPU: Radeon HD 6790 RAM: 4GB P.S. I've tried on 3 monitors and still the same problem, also i've the cables (monitor & power cable)... I don't think its the graphics card as when it does work, it works brilliantly. But most of the time when i turn it on the monitor gets no signal.

• Answer:

  There are a number of things that could cause this. The main one could be your graphics card. I know you said it works great when it actually works, but that could be the cause. Another key problem could be your power supply. This sometimes may not be giving enough power to the motherboard, causing insufficient power to be given to the graphics card. One solution might be (no guarantees), try getting a new power cord for your computer. Your current one could have a bad wire or something causing insufficient power to be given to the power supply. Your best solution would be to take it to your nearest computer store and have them run a test on it to see if they might know. I hope this helped in some way :)