What are other causes of a phone not turning on besides a dead battery, overheating, and freezing?

There are a number of stories about various devices smoking or even exploding - mobile phones, tablets, laptops, E-cigarettes etc. They all seem to revolve around battery/charging faults where the Lithium-Ion batteries have overheated or expanded causing the device it's been installed in to be damaged.

The battery must be failing replace the battery it may catch fire.

I had similar problem with HP tablet which was not answered by them. Later I found it has got DEEP DISCHARGE problem.ie. it is allowing the battery to go to deepdischarge stage due to circuit problem. The circuit should make itself dead and prevent the battery to go to that level. Virtually the battery enters into COMA stage ! Keep it in switch off stage for 48 hours with charging on - so that the battery comes to life again and charges itself. Later my tablet is OK.

multiple issues can cause this. the first is an aftermarket protective case, the second is continuously overcharging it. the third is program(s) running in the background that will not shut down. The battery may be damaged as well. Step one is reconditioning the battery. run it until it is dead, recharge it until it is JUST charged full and disconnect the charger and run until dead again. This should eventually increase the time between the need for recharging if the battery isn't damaged. If it has an after market case remove it while doing this. If it is an android, download a handful of utilities from CM (free) starting with their Battery Doctor and their antivirus ( they are the best known and respected android developers) and run them. you can do this while you are conditioning the battery.
Battery Doctor will take over for the other apps that are telling you the tablet is overheating. and will automate the process of taking care of whatever is causing problems.
I use them on my Tablet and my Samsung Smart phone

The white dots are most likely to be failed pixels in the LCD screen. When the picture elements fail, they switch to clear and what you see as white is the backlighting.

The overheating issue in laptops is generally caused by dust and fluff blocking the cooling fins and ducts or a failed cooling fan, but it could also be caused by a hung process which runs the CPU at a high processing speed. Press control (CTRL) ALT and DEL and look at the task manager and see if you can see any processes that are running constantly near or at 100% to eliminate this being the problem.

The failing display is unlikely to be related to the overheating issue.

If you allowed the battery to go dead you will have to remove the back, unplug the battery, then take an old phone charger cut off the plug that goes into the phone, strip back the wires hook them (in the proper polarity) to the battery and plug it in and allow it to charge for a little while, every time my wife runs my battery dead on my Asus Memopad I do this overnight, in the morning plug the battery back into the tablet and you're ready to go. VERY IMPORTANT! get the battery and charger polarity correct, the battery wires are usually red +, Black - I hope this helps you

i want open my tablet

It could be a number of things. Too many programs running. Or prolonged use while on charge could cause overheating.

seems like a hardware problem...Hard Disk Probably.but don't take chances...first remove any external hardware attached [usb,printer etc.remove the battery also]then try to install the OS use another CD or you can even use Windows XP.Make sure you change the SATA setting in the BIOS for XP. You did not mention the error message or when does it hangs while installing Vista.Try changing the Hard Disk.If there's still problem then it's your motherboard. As far as overheating is concerned you need to see how long does it remain powered on.And when you switch it on again does it turns off quicker than before. Take it to the service center.