Today I switched on my laptop and found there's a largeish mark on the screen like a halfcircle that looks like a watermark . Just before I cleaned the screen with a wet tissue - normally I us lens wipes or a damp towel but I've used wet tissues or towels before - is it possible some water got inside the screen ? The mark won't wipe away . At first I thought it was just the display but then some keys on my keyboard stopped working and now my computer seems to be slower than normal. I phoned Dell support and they said I could buy a new display for £160 but they said I should just buy a new computer as mine is now 3 years old. I really don't want to as I don't want Windows 10 - I found a replacement display for my model laptop from Amazon for about 50 - I also found a replacement keyboard for similar price .But I'm, still worried there may be other damage -- I ran diagnostics which didn't find anything and did a system restore to before Christmas, which didn't change anything - the keys still don't ok and it still seems slow.
I'd be extremely grateful if anyone can offer advice - it seems too much of a coincidence but I can't believe some water could do damage apart from the display - it seems odd it should affect the keys?