Why does my computer monitor turn on and off?

When i turn my computer on the monitor comes on then goes off, why?

• when i turn the computer on the monitor goes on then off after about a quarter of a second and does this continually. if i turn the monitor off with the button at the front and wait a few seconds and turn it back on again it sometimes fixes it and nothing happens again. on other occasions it sorts itself out after a few seconds without me having to do anything. it only just started a few days ago and im not sure why. i was thinking maybe its because of the cold due to it being winter but not sure if its the reason. i have checked all the connections to the computer and at the back of the monitor, unplugging and re-connecting and that has made no difference. anysuggestions would be greatly appreciated. thank you and happy christmas

• Answer:

  Could be an issue with the monitor, but I suspect the monitor isn't getting enough power. Are you running the PC and the monitor off the same plug socket (or extension), if so, you shouldn't be. Try putting them on seperate sockets.