Is the lead permanently attached to the Monitor? If not, try a substitute lead.
Check for bent pins on the connector plug.
Digital or vga connection?
If all of the 'obvious' things check out OK, it's likely the Monitor has failed and it looks like a repair job.
Check out your local TV repair shops, they're generally cheaper than specialised computer repair places. And ask for a quote if possible, to see whether it's worth repairing or not.
As it's a TFT Monitor, it probably is worth repairing.