If you are part of an "organization", contact your IT department and they will activate Windows. If you bought this for home use from a sketchy place that sells stuff that fell off the back of a truck, your best bet would be to install a Linux operating system, which is free forever without worrying about a license.

I'd guess that bluetooth has about the same range as a set of cables, so kind of pointless because they don't have the sound quality of the built in speakers. But it seems to me that if you can interface with a tablet, it would also work with a bluetooth speaker or earpieces or headset. That would allow you to shut the internal speakers off and practice quietly.

A "missing" component might not be a problem. Designs change all the time and it might not be needed. That looks like a capacitor, anyhow.

I just did this with a new Samsung phone. It has a transfer app that worked OK, but now I have a bunch of apps that I never used and some duplicates. I'm not sure it was worth the trouble. When changing computers, I make a list of all my apps, then just install new ones on the new computer so I have fresh, useful ones that work with my new operating system.

Check the pins that connect the charging case to the buds. You should get about 4 volts DC on both. If not, something is broken inside.

First step: your thermostat could be stuck closed. See if the radiator gets hot. If not, take the thermostat out and see if that fixes the heat. It should run cold then. If not, you might have a bad water pump.

The red and black wires are pretty obviously positive and negative of the battery, but I don't know what the rest do. Possibly monitoring voltage, or heat sensing, an interlock, or unconnected. If you can't find a mating connector set, you could splice in some wires, maybe with your own connector. It would be safe to do, but I don't see what advantage this would get you to have an external battery 20 cm away. Better to use an external battery plugged into the power jack. Those connectors are easier to find, and have just two connections. You would need a charger for the battery, though. Check the voltage output of the existing power supply. A "12 volt" car battery might put out 12.6 volts, so if you are worried about the extra voltage, just use a power diode in series with the positive lead. A diode rated at 50 volts at 3 amps is very cheap and will drop the voltage 0.6 volts. You can put more in series if need be. If you are running in a car, use an auxiliary power port (cigarette lighter) jack. You can...

That could be bad. Either there's a short inside the PC or the battery is dead. Make sure the charger is the right voltage and current rating. Check the output with a voltmeter.

On our Mazda, it means the key fob battery is dead. They die once a year or so depending on how often you use them. It's always good to have a couple on hand so you're not rushing out and paying top dollar at a drug store. They are cheaper online. There's probably a place to pry it open with a small screwdriver, but be gentle.

Not a bit. But be careful that it is mechanically sound, so that it doesn't break again.