Sounds like a connection not making proper contact. Unless you are conversant with dealing with high voltages do not open your monitor, I suggest you have a chat with your local TV repairman as monitors are very similar to TV's and he may sort it out for you. If you wish to do it yourself, leave it switched off for at least 12 hours before opening it up, even then you can still find high voltage lurking where you least expect it so be very careful. Look for any plug-in connectors, remove and replace each one in turn so that you don't get them mixed up and do not force anything, if you break it it means either a repair or a new monitor. Once you have gone over all the connectors you can see if that has fixed it by trying it out. You may hve to replace the case for this as many monitors get their strength from the cover and cannot stand safely without it.
Hope this helps, Barry

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