Loose ground connection may be breaking the electrical circuit, then "jiggling" around may make the intermittent connection again, allowing the car to start.

Brad: he did mention he changed the battery. Bev: is your phone getting really hot when it drains fast? there may be a short or damaged connection that could be causing your battery to drain

Personally, I've had no problems with OWC's memory matching. As David mentioned, the pins should tell you what motherboards the ram modules will fit into, but the MHz determine which logic boards it may be compatible with. Feel free to check with Other World Computing and make sure they not only fit your motherboard, but are also in the proper speed range for compatibility before ordering the ram modules. Also remember, just because the ram is a larger module (more GB) doesn't mean it's going to be faster (MHz) than the ram that's already in there.

Sounds like it's just the battery. A lot of modern electronics get hot while under heavy use or long charging intervals, including laptops, phones, and tablets. If it's hot enough to burn your skin, there might be an issue, otherwise I'd chalk it up to the battery/processor just working hard.

Most likely issues in order of probability: 1) The cable could have broken internally 2) The electrical connection of the power socket to the logic board may be broken and making intermittent physical contact 3) Your battery may have worn out and refuse the charge.

If your fans are turning on and off with the power button, then your computer is most likely starting. Have you double checked to ensure all the cables, wires, and connectors were properly routed and re-connected upon re-assembly? It seems your display may have disconnected from your logic board, leading you to believe your computer is not turning on when it actually is.

I'm gonna agree with Mayer's diagnosis: on these computers devices that require shadow power from the USB port (if they have an optional dedicated power outlet that is not being utilized) the USB port on the left side (the same side as the magsafe adapter) is probably the one that is going to work. In the unlikely case that it not a shadow power issue, a faulty USB cable MIGHT explain it, but my money's on USB power.

When you plug it in, iTunes should tell you.

Seems to me one of the ram modules may be bad or may not like being mismatched. Most important things to note when installing ram: 1) NEVER touch the pins on the chip with your fingers, always hold the modules by the sides of the wafer. 2) ALWAYS be wary of ESD, make sure you are grounded or at least not wearing socks on the carpet when opening your computer and accessing ram. 3) It's not necessary, but most ram problems come from mismatching chips. Most ram today is sold in dual channel, 2 module packages (6 gb max ram usually forgoes this), but Macs seem to prefer matched module sizes. That said, I've installed a 4gb module with a 2 gb module in a computer one generation older than the one you listed and had no trouble at all. Re-seating the ram is merely popping the modules out of the socket, perhaps blowing out the socket with a can of compressed air, then re-installing them carefully and evenly, being sure they are flat, flush, and fully inserted into the socket. Perhaps try running the 4gb module by...

Have you tried with a friends (known working) battery? The fact that it is new is usually good enough to assume it's in proper working condition, but does not always guarantee it. Before sending it back or buying a new one, I'd suggest trying a battery that works in another computer first if possible