Yesterday my GNR crt 17 inch monitor gave me the message, Warning signal out of range. Other monitors Ive tried since work ok.Since the shop from where it was purchased has closed do you think I should scrap it. Its 18 months old.
Make sure the resolution and refresh rates are set correctly, for that particular monitor, in Control Panel > Display, hzhzhz. It could also be that the monitor's 'power supply' has packed in, in which case take Diodorus Siculus about getting it repaired. Don't try to open the monitor yourself, there are high voltages in there which can kill.