After years dead, MacBook display suddenly worked, until PRAM zapped A couple of years ago, I got liquid in my MacBook Pro 5,2 (Unibody 17" Early 2009). After that, the display never worked. Apple Stores and Authorized Repair places insist on me paying over $1000 for a full logic board replacement before they'll do anything else to it, so I've been using it as a desktop machine with an external display since then.

Sometimes I leave the computer's display propped halfway open to help with heat. It's been that way for days. Tonight I briefly had a USB hub go funky, with lights blinking that shouldn't have been blinking, so I restarted the computer.

When it restarted, the years-dead display worked. But it didn't work perfectly; solid-white and solid-black areas flickered shades of yellow, green, and blue incessantly. But those flickering corrupted areas moved perfectly with app windows as I dragged them around, so I think it was some kind of corruption of the graphics data and not physically broken display pixels that I was seeing.

I was elated, and started trying to fix the display. First, I rebooted. Didn't help; after the reboot it looked just as it did before. So, step 2, I zapped the PRAM.

On that reboot, the display stayed dark, just as it has for years. I zapped the SMC after that, and the display is still dark. Clicking "Detect Displays" in System Preferences doesn't help.

I'm furious that this thing got my hopes up and immediately squashed them. Is there anything, no matter how complicated or technical, that I can do to make this thing acknowledge that display? I am 100% comfortable with the command line or anything even more arcane that I need to try.
Well speaking of "arcane",and "those kind of guys" are still around, for clarity see the answer below :) 

So what you need to do is open it, remove battery, and clean the mother board and plugs ect.... using NON metallic cleaning objects like toothbrush and q-tip. 

Use alcohol (for grease) and Vinegar(or pure lemon juice without sugar) for calk deposits from your spill. 

The density of interconnects is very high and even a small amount of semi-conductive dirt can do what you are experiencing, so give it a good scrub.

Good luck :)