Changing main account name

I've had my 2nd hand Macbook a few weeks now, and am yet to work out how to change the main account name into my details. How do you actually change this info - i've tried everything in the system preferences panel, and I can't see any useful utilities to try.

Any tips?

To change the name go to  menu > System Preferences > Accounts

You may have to unlock the brown padlock in the lower left to make changes

Check this:
Mac OS X: How to change user short name or home directory name

Hmmm... somethings up with my OSX. I can't change the short name (downloaded the application 'changeshortname', but it says my ID doesn't exist so therefore it can't change it).

I also noticed in Disk Ultility - having just bought a WD HD I now need to format to OSX and partition the drive to suit. But - I got no Partition tab to choose. What's going on here?

Whenever you purchase a pre-loved machine, always format the hard drive, zeroing if necessary, partition and do a clean install so you are not carrying over someone else's password, corruptions etc. Take it the system discs did come with the machine which is vitally important?

To partition you boot from the install disc, holding down 'C' after the chime, go into Utilities in the Menu bar, select Disk utility, and format and partition there. Remember you must also click on Options to select GUID partition map.