So, to start these computers have Solid State Drives which are fairly resilient against drops. It's odd that you would be getting boot device not found screen after the drop. Either way I would open up the computer(be mindful of electrostatic discharge, ground yourself or use a ESD strap) check all the connections on the board and the connection for the SSD. Something might have come loose from the drop. Here is a guide on how to get into the computer and to the SSD, it will also tell you what tools will be needed: MacBook Pro 13" Retina Display Late 2012 SSD Replacement

That should work fine. The only issue is is that it might be an IDE drive and your newer machine will most likely only have SATA connections. Pull out the old drive and look to see what connection type it has if it's sata you should be able to transfer it to the Windows 7 machine, boot it up and see it as an available drive with the data on it.

Try a static reset. To do a static reset you need to disconnect the battery, then hold the power button for 10 seconds. It looks like you computer is a bit more involved for this. This video shows you how to remove the battery on your laptop. https://www.youtube.com/watch?v=UWB35_tN... Also this guide for the x551ca models seems very similar Asus X551CA Battery Replacement As you have to pull top off to get to the battery I would just remove the battery and let the computer discharge for 10 - 20 minutes with the battery disconnected. if you can hook up the top and press the power button with the battery out that would be faster. After you have done a static reset boot it back up and try charging.

First, we should solve why id doesn't boot. What do you see on boot? What type of screen? Any icon like a folder with a question mark? What have you tried so far? Second, the keyboard can be replaced. Unfortunately you will have to replace the top case on the computer. Upper case replacement guide here MacBook Pro 13" Retina Display Late 2013 상단 케이스 교체 . The parts for this are here MacBook Pro 13" Retina (Late 2013-Mid 2014) Upper Case Assembly So to replace a keyboard is expensive so solving the boot issue is probably a good place to start as the computer could be used with an external keyboard and mouse as well. Also what version of Mac OSX you are running would help(if you can remember)

A lot of computes will check for a working fan and throw an error if it doesn't find one, or it's not spinning. Unfortunately the Macbook pro that you have was not designed to work without a running fan and will most likely overheat fairly quickly and shut down again. I would not recommend running the hardware without a fan as the Processor is not designed to be passively cooled like the new Macbook.

Make sure it is not disabled in system settings(instructions here: http://www.tekrevue.com/tip/pair-disable-macs-ir-remote-receiver-os-x-mavericks/), I am assuming it is not working?

Boot the computer into the recovery partition (hold Command + R during boot) and run Disk Utility. In disk utility run a verify on the hard drive and see what results you get. If that comes back bad, try to run the repair. If it is unable to repair the disk, I would backup your data and then reinstall MacOSX.

There are a few things to check. 1) Is it under warranty, assuming it isn't because you are here but have to check. 2) Try turning it on by bypassing the power button, the question here has instructions on how to accomplish this. Where is the power jumper on the logic board? *edit* (Check here for your model and where the pads are located) http://www.insidemylaptop.com/turn-on-macbook-pro-laptop-without-power-button-locating-power-on-pads/ The initial hard shutdown is interesting if the power button has issues maybe it triggered a hard shutdown and won't work to turn it back on. 3a) If bypassing the power button didn't work take a look at the magsafe board(MacBook Pro 13" Unibody Mid 2012 MagSafe DC-In Board Replacement) and inspect it for visual damage, also check your battery for swelling and see if it has charge(battery indicator button). Also does the power adapter have an LED light when plugged into the computer? If not the magsafe board might need to be replaced. 3b) If the bypass does work congrats,...

Try booting the computer while holding Command + R. This should boot the computer into the recovery partition. From there you can open Disk Utility and check the health of your Hard Drive. Once you open Disk utility select your hard drive and click the First Aid tab. Then click verify disk, if this comes back red your upgrade to El Capitan may have gotten corrupt. If you have a backup awesome, if not you can try to backup through target disk mode. You are able to reinstall Mac OSX through the recovery partition as well, you do not want to reformat your disk just install. The install should not touch your data but I recommend you have a backup first either way.

Worst case your battery is worn out and you need a new one to restore longer usage on battery. I would first check the windows task manager and make sure that you do not have a process with high CPU usage(this will drain the battery quickly). Also closing background tasks can help reduce CPU usage and increase battery life. General maintenance as well, such as defragmenting the hard drive can make the computer have to work less and use less power. If you let me know what version of windows you are running I could tell you how to remove startup programs and background tasks.