2709W, blue or pink screen issue

For the last few years my good old 11 year old monitor has had a problem: sometimes (mostly when the power of the house suddenly goes off) it shows a full pink or a full blue screen. When this happened, I used to turn off, unplug all the cables, plug again and turn on again. After various attempts (3 to 10-ish) the monitor used to work fine again. But now, for the last months, I've been in the situation of no matter how many attempts to turn off/on again I make, I get a blue or pink screen. What part could be the problem? I would exclude an issue with the power, since it always turns on correctly. Is there a replacement attempt I can make in order to try to make it works again?