A backup is a giant ZIP (Compressed Folder) file of sorts. If you are on Windows XP, you should be able to Press the Windows Key (The one that looks like a flag, but in fact is a window) and R to recieve a box that reads, "Run". In the typing Space, type ntbackup. (If it doesn't work, Don't fret, there are plenty of Free Backup Software on the net, but be careful!) And a box should come up and tell you about backup, just go ahead and click next. I should say "What would you like to back up?" or something to that effect, make a choice, and click next. it should give you all this information about your choice, and ask you where to save the backup, select your External Harddrive (Flash Drive, Thumb drive, etc.), and click next. Click next again, and it should start the backup. You CAN still use your compute, but it WILL be slower.
II. What do I do know?
Wait an hour or so, until it finishes, then you should be good to go.
I. Woah Woah, Back up... Whats a back up? (Windows 7)
Your Action center should be freaking out about how "You have not backed up your system in *Blah Blah* days".
Go ahead and please your machine by clicking the "Backup now" button in the Action center. Repeat above.
If you need help backing up, or want shoot me an Idea or Comment, send me a friend request and a message, and give it to me!