The main thing to remember with regard to resetting your PS3 is that there is the potential to lose a lot of information. A reset returns the video game system to factory condition and reverts any setting changes you might have made to the original default status. Depending upon how much customization you've made and how long you've been using that particular PlayStation 3 console, a reset could be a very big deal. On the other hand, if you store most of your game progress and changes on removable media, the fallout could be less severe.
There are various conditions that might call for a PS3 reset procedure. If there is no hard drive activity or the system freezes up when you try to use it, reset might be your only resort. If you have any doubts, call customer service first and make sure there isn't something else to try. As mentioned, a reset -- sometimes called a hard reset -- removes any changes you have made to the software on the machine's hard drive, returning it to factory condition.
To understand the severity of the term "factory condition," it will be reset back to the same status it was the moment you bought it. A reset literally deletes all information from the hard drive, reformats it, then installs a clean version of the operating system. When a PlayStation 3 begins to freeze or suffers other type of problems, it can mean that the software has picked up a bug or become unstable for one reason for another.
You should be aware that PS3 consoles come with slots that hold removable media -- game cards -- that allow you to save information, settings and even game saves. If you've been working your way through Call of Duty for months, for example, a reset could erase all that progress unless you have the foresight to create regular system backups or save the information on a card. Once you send your PS3 into reset mode, there will be nothing left on the hard drive to reclaim.
If you're a serious gamer, or even only use the PlayStation casually, a frozen system can be one of the most frustrating scenarios you encounter. If you run into a system freeze and have not been performing backups or using game cards, you could lose all of your information. A PlayStation hard drive is similar to those found on your desktop or laptop computer, and like these digital cousins, your best bet is to plan for hard drive failure, because some day it will.