Data is the more important part of any electronic hardware found anywhere. Data is the part that contains instructions to control how the electronic components behave. Data is also the part that holds information in a way that when displayed on a computer monitor, it will show words and images.
Sometimes, something can go wrong somewhere and that will force the data not being accessible. Luckily, most of the time, that data can be retrieved so that you can use that data on another working digital system. Unless, of course, the part that holds your data is destroyed beyond salvageable means the you are out of luck.
If you suspect of something wrong with your computer and find that data is missing, immediately shutdown the computer and get in touch with a specialist.