Hi guys, I wonder if someone can offer me some advice? I bought I macbook off ebay with a known fault. The seller reported it shuts down after 20-30 minutes of use, and the fan grinds loudly sometimes. It sounded like a pretty easy cleanup and maybe replacement fan. I've been playing with it for a few days now. The fault was as described (though the seller failed to mention that the screen had some discouloured patches of what looks like liquid damage and two of the keys including return don't work!) So I thought I'd open it up and have a look. I've never worked on an apple laptop before, but have repaired many windows laptops. I was following the illustrated disassembly guide from powerbookmedic. Anyway, this macbook was filthy inside. Really really grubby, with sticky patches where it's obviously had a drink in it, and mainly full of dog hair! The heatsink and fan were clogged with it so it's no wonder it had overheating problems. I pulled it all apart and cleaned it up. I spent hours with cleaning cloth and a toothbrush. I replenished the dried-up thermal grease on the heatsink. I've put it all backtogether... ...and nothing. I seem somehow to have killed it! I followed anti-static proportions as normal (wrist strap etc) and was very careful. I'm sure I got everything back in the right place, but now I get absolutely nothing. When I hit power, nothing at all, no sound, no light and nothing on the screen. The battery is showing fully charged, and when I plug in the magsafe power cord the light goes green after a second. I've just re-seated the RAM and HD, which didn't help, and just followed through the top case removal procedure again and reseated the keyboard/touchpad connector - still nothing. I'm a bit stumped now. Since I'm new to mac, I really don't know where to go next. What diagnostic steps would be best to take now? Thanks a lot for reading!