Summarize:

A "soft reset" simply refers to forcing the Kindle to restart. This is the first thing you should try if your Kindle is frozen or not working properly. Before performing the soft reset, plug the Kindle into a wall charger. A lack of charge may be causing the problem. This will force the Kindle to turn off, regardless of whether or not it is frozen. On most Kindle Fire models, the Power button has the traditional Power icon. The 2012 Kindle Fire HD does not have an icon on the Power button. Make sure to press and hold the button until the screen turns off completely. Give the Kindle about 15 minutes to charge before trying to turn it back on again. If you know that it had a full charge, you can go ahead and skip this step. If your Kindle isn't charging, there could be a problem with the charging cable itself. Try a different charger to see if you can get it to charge. Check to see if your problem has been fixed. If not, you may want to try a full factory reset.
Try a soft reset to see if your problem gets fixed. Plug your Kindle into a charger. Press and hold the Power button for at least 20 seconds. Allow the Kindle to charge for a little bit. Press the Power button to turn the Kindle back on.