I have had a rash of problems recently with laptops, all related to batteries. If you use a laptop, make sure it’s plugged into the wall overnight – if it’s not, it may go to sleep, and be impossible to wake up the next morning, or it may discharge completely. If you are thinking about buying 
a laptop, check that the battery is easily removable.
If your laptop does not turn on, try removing the battery, plug it into the wall, and try again. How long will a laptop battery last? 2 years is not atypical. Be aware though – a battery can become non-functional very quickly (I’ve seen one go in as little as 2 days). Batteries Plus on Route 9 is an excellent resource if you need a new one.