I have a 17" CRT monitor.Recently its been causing some problems.When i try to turn it on it just doesn't bring the display immediately.It starts making sounds like there is no display attached but system is running as i can hear sounds of OS and then after 1-2 mins of constant making-clicked-sounds i shows the screen.If i turn off screen for 5 mins then it isn't much problem but if its for about 15 mins or above then it starts giving this problem and shows the screen after a long irritating time.
Your screen is faulty and is probably a serious fire risk as well. Unplug it from the wall and replace it with what you can afford. The cost of fixing it will probably not be cost effective. It does not sound like it is the GPU. Remember many house fires start due to faulty TV's and Monitors.