LG Flatron monitor problem
It is often difficult to diagnose/repair an intermittent problem. It could very well be any of the circuitry and components inside: video interface, CCF Lamp, inverter, power supply. All of which would require that you open the casing and poke around inside and that you be familiar with electronic components & circuitries, soldering and use of a continuity/volt meter.
Doing so would void your warranty (being just a couple of months). Perhaps your best bet would be to seek repair/replacement of the monitor from your dealer/supplier and describe fully the nature and frequency of the incidence. It may be that when they test it will check good.
Should you choose to open it up yourself, post back.
Good luck and kind regards.