It sounds like the expensive part (the lcd screen) is ok, its probably a fault with the video board inside the monitor, this could be replaced/fixed. There could also be a problem with the power board. if it is either of these, the monitor needs to be serviced by a professional. you could try plugging the monitor into a different computer, if this is the problem it means you need a new graphics card, or need to re-install the graphics drivers on the computer.
Answers & Comments
It sounds like the expensive part (the lcd screen) is ok, its probably a fault with the video board inside the monitor, this could be replaced/fixed. There could also be a problem with the power board. if it is either of these, the monitor needs to be serviced by a professional. you could try plugging the monitor into a different computer, if this is the problem it means you need a new graphics card, or need to re-install the graphics drivers on the computer.