Originally Posted by Good Voltage
I see, but given that the keyboard incident was 3 months ago and the power off problem just started, do you still consider this the most likely source of the problem?. It was not a lot of water like an spill. If the keyboard problem was due to water, it would have been that some of the wetness of the tissue made it past the keycaps. Are laptop keyboards closed on the bottom?.
I think it is possible for the damage to progress over time, yes. And no, they are usually not closed on the bottom. They are porous on the bottom as is the palm rest that they snap into. Regardless of whether it was caused by your cleaning the keyboard or not, I'm leaning towards motherboard failure. You can try reseating your ram and processor. If you do indeed pinpoint the motherboard as the failure, you can try a solder reflow as a last resort. Perhaps others will have more ideas.
Oh, and as I forgot to mention, welcome to the forums. Feel free to introduce yourself in the Lounge area. There's a good bunch of members here and I'm sure you'll be able to both give and receive quality advice!
EDIT: another thought that crossed my mind: check your ports for any damage. bent pins in USB ports are super common and will short a motherboard. Just spitballing.