User folders - how to change names

[miss mouth]

i am selling a laptop to a co-worker but am having troubles changing the user name. This is windows 7 home premium 64 bit. The folders under "users" are the "public" and the my name. I want to change it from my name to their name but it has a lock symbol on the icon and I cannot figure out how to do it.
I was able to go into user accounts and change the name there, no problem. But the "users" folder will not change also.
How do I do this? I do not want to do a fresh install or anything - this laptop is only one month old but I ended up not liking it. I already installed Abode professional, Office Professional 2010, and a bunch of other software that the buyer is paying me extra for, so doing a clean install would screw that up for them. Is there any way to change the folder name or are they just stuck with it?

 

[mibix19]

Hi,. Go to Control panel \ System.On the right click on change settings then click on change computer name.( below the box which says 'give this computer a name') Change your name for the person who is buying it