UPDATE to the earlier UPDATE (below)
Turns out that the apparent resolution of the problem resulting from the new battery was short lived. The problem is still there. Will review the suggestions provided earlier and see how far I get
UPDATE
At time I had requested help on the turquoise display issue, I had placed an order for a new battery for the laptop as it was completely dead. Well, the battery arrived and after replacing it, the display returned to normal white. I hope there is a rational explanation for that. Needless to say, I'm happy. Please let me know how I must close this issue. Thank you again for your attention. Best,