With the age of your computer I would recommend getting a new one. With the labor required and any possible new parts or even an OS reload the cost would far outway the worth of the laptop. I believe you would be very happy with a new laptop. I recommend ACER or LENOVO laptops, great customer service and good bang for the buck.
here is the cheapest replacement part i found on ebay and dont forget to check out the repair guide here on iFixit guide 3DS XL Repair part http://www.ebay.com/itm/P-Replacement-Analog-Controller-Joystick-Cap-Part-for-Nintendo-3DS-3DSLL-3DXLL-/291576463392?hash=item43e34fc020:g:WpkA...
If the original home button still works you need to put it back in if you want to use touch ID, apple has it so that only the original home button or one that they put in themselves will work with touch ID. any new home button will not work
I pulled this from theandroidguy.com GALAXY S5 SCREEN FLICKERS WHEN BRIGHTNESS IS SET AT CERTAIN LEVEL Problem: When the screen brightness is lowered to the lowest setting, the lower half of the screen begins to flicker. Raising the brightness a few notches stops the flickering. I have not dropped the phone or exposed it to water – the issue started out of the blue and it’s driving me mad! Please help. Troubleshooting: Screen flickering issue can be hardware or firmware problem and since there’s not much information here, you have to other option but to rule out the possibility that it’s just a firmware issue (which I really think it is) by performing hard reset. Of course, backup all your important data before doing that as they will be deleted. Turn off the device. Press and hold the following three buttons at the same time: Volume Up key, Home key, and Power key. When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key. When the Android System...
Have a local technician test the battery. a bad battery can over heat and not stay charged. If it does end up being the battery here is a link to one on ebay. http://www.ebay.com/itm/NEW-EB-BG800CBE-Battery-For-SAMSUNG-GALAXY-S5-mini-SM-G800F-2100mAh-/171729519892?hash=item27fbe08514:g:O64A...
The charging port is soldered to your logic board, the only way to fix it would be to micro-solder a new one on. otherwise you would need to replace the whole board.