Liquid Damaged MacBook Pro Randomly Powers Up

Hey everyone,

Having unusual problems with my MacBook Pro and was hoping for some insight. This last weekend I was DJing a party at my Bosses house. Apparently I wasn't playing enough Flo Rida because one of his room-mates asked to hookup his laptop and play a few songs. I came back an hour later and there was a puddle of beer on my keyboard. I powered it off immediately, took it home and dried it out for 72 hours. It turned on fine, functioned perfectly. Next day it did not turn on. I did some research, and since all my data was backed up I decided to try some things. I reset the PMU using the remove battery/unplug method. Laptop powers on and functions perfectly. Next day, won't come on. I resent the PMU using the ctrl/option/shift/power method, turns on, functions perfectly. Next day, no dice. I work at a place where computer repairs are done, so I asked a tech to check it out. It was bought used so no warranty to worry about, we opened it up. Everything looked very clean, all the liquid seemed to be in the keyboard which was working fine, but it wouldn't power on. I gave up and bought a new laptop on craigslist, which had a brand new battery. On a whim today I put that battery in my old laptop and it powered up fine, worked perfectly all day. I shut it to go home, now it won't power on. My co-worker believes it to be a voltage regulator issue, I have no idea, other than that it seems unusual. My old laptop is a 2006 Core 2 Duo 15" Macbook Pro with a 300 GB hard drive with a 48 GB SSD where the OS and user info is located, new one is a 2006 Core Duo with a 250 GB drive. Obviously, I'd like to get my old machine back. Any ideas as to what might be going wrong would be greatly appreciated. My apologies if I've left out any obvious info, and sorry for the novel.

Oh, one more thing. On the unsuccessful attempts to power on the machine, I could feel the Hard Drive spin up, but the screen stayed black and OS never booted. Occasionally the Hard Drive would audibly power down after a few seconds.

Thanks!