How to change my computer's name

How can I change my computer's name?

I found out while trying to backup my computer with Time Machine that after I reinstalled and rebooted from my last saved state, my computer's name changed slightly. It used to be "Daniel's Computer" and now it's "Daniel's Computer (2)". Because of this I can't use my previous states to backup and I have no space left to back up the whole computer.

Please! Help!

Ok found out how to change my computer's name (System Preferences/Sharing). Problem not solved though. Now my computer's name on the Time Machine is the one with the "(2)" beside it. WHAT CAN THIS BE????????