You must bootup your workstation (load the system into memory from disk) after a system crash, a hopelessly confused communication network, a power failure, a shutdown period, or making certain modifications to the system. While the system is booting up, it's a good idea to check what's being written to the console and note any numbers on the machine's light-emitting diode display-if there is one. While this may not be an exciting way to spend five to ten minutes, it is something of a tutorial on the contents of your system and can help you locate the cause of problems when they do occur (and help you feel less foolish when you describe your troubles to that experienced friend). During boot up, the computer may ask you to enter the date, the time, and whether you want the system to check the correctness of its own file system. Do not just ignore these requests because you are anxious to get on with it; having the correct date is important in order for you and the system to keep track of which are new and which are old files, and having the system find and then correct errors in its file system with fcsk can prevent catastrophic problems later.