Because it's broken. You need to replace it to get it working again. If you haven't voided it already, your device should still be under warranty with Apple, and they will replace the camera for free.

Is it just those buttons in landscape, or is touch in general not working on that column or row on the screen? If the touch in general is not working, it very likely needs a new digitizer/LCD assembly. Technically you'd just need the digitizer, but it's adhered to the LCD and it takes quite a bit of practice to do glass only repairs.

Drops can cause solder balls and joints to crack, as well as cracking the chips themselves, which are basically pieces of glass. If something doesn't work immediately after a drop, you've basically broken some sort of electrical connection in the phone, or have cracked a chip on the logic board. In your case, the problem manifested itself later. Sometimes a drop will weaken components, and a slight gust of wind (using this as a figure of speech, not a literal gust of wind) can finish them off. Most of the time I've seen this happen though, it's because the crack in the screen made the device less resistant to moisture, and liquid spills can more easily get in the device. Even in the absence of a spill, moisture can get inside the device more easily and oxidize components, causing them to not function as well as intended, and if the oxidation is bad enough, a circuit on the phone can fail, or multiple circuits can fail. Get oxidation in the wrong place, and the whole phone stops working. The drop could very...

There's likely corrosion on the phone's logic board, causing components to short. Your best bet would be to take it to a shop with an ultrasonic cleaner. Make sure they have one, because alcohol and a toothbrush tends to do more harm than good, and most shops and technicians are clueless when it comes to proper water damage repair. If there's not one in your area, you can mail it out for repair.

The Galaxy S2 is an older phone, and you may find difficulty finding a repair shop that will fix it for you. You would probably be looking at $60-80 for a repair, but it's unlikely that they'd have the part in stock. Unfortunately, that's roughly the cost for a used Galaxy S2, so if you don't need to fix the phone to get your data off the phone (always back up your data! Use something like Dropbox or Google Drive), I would just get a new one. I would try calling a few local repair shops in your area, but you're likely going to have to wait a while to get it fixed. Talk to T-Mobile and see if they can get you hooked up with a loaner phone.

The most likely cause of this would be a torn or kinked cable. Typically the LCD back plate and cable are transferred to the new LCD assembly. The LCD assembly itself has nothing to do with the touch ID -- the home button plugs into the cable on the back plate. It's also possible that a connector might not be seated properly.

Are you certain that the power adapter is working fine? If you have access to a multimeter, it should be measuring around 19-20.5V. The service manual seems to indicate that 4 flashes means the battery is critically low. http://tim.id.au/laptops/acer/aspire%205...

MacBook Pros, particularly the 13" model in my experience (although that may have been just because they were way more popular...) absolutely have an unacceptably high HDD cable failure rate. However, that's not always the cause of the "flashing folder" issue, which means that the machine couldn't find an operating system to boot from. If it were a HDD, I'd immediately ask if you'd dropped or bumped the machine. However, SSDs are much more shock tolerant. That doesn't mean you can throw one across the room -- solder joints can still crack very easily -- but it does make it less of an issue. Still, if you've dropped the machine, that may clue us in to what's going on. SSDs have had a rough start -- they're fairly new tech -- and certain models have had high failure rates. What model of SSD do you have? Also, if your machine has this capability (it may be a year or two too old), check to see if your drive is being recognized at all. You can do this by holding CMD + R right after powering on the machine. If...

High/max speed fans on a Mac are generally the result of a sensor not being able to be read. If the thing came all the way off, it'd need to be soldered back on... assuming that the pads are still intact. The battery should be fine. CR/BR doesn't look like it matters... I wouldn't worry about replacing it until you need to. Any way you could post pictures of the images the machines getting?

Has it ever gotten wet? Has it been dropped recently? A lot of the time the charging ports will break on these things. Does the actual port look okay? The flat plastic "nub" inside the port should be flat, not mangled up. Does the device get warm at all when it's on the charger? If you're around a Batteries+Bulbs, give them a call and see if they have a battery in stock for your device. Unfortunately, your phone doesn't support wireless charging as far as I can tell, so you wouldn't be able to simply throw it on one of their chargers and see if it works. Unfortunately, there's little I can do over the internet for a no-power issue. Normally I'd recommend taking it into a shop, however most shops don't have the expertise to repair what could very well be a board-level repair job. At the very least, you could try finding a place that does free diagnositics and having them open it up and inspect the device for damage.