You can change the size of the icon and the font under the icon in control pannel - desktop but that's not what this is about. This is to change the name of the icon. I will use the Recycle Bin as the example.

At the "Start" menu enter "Run" and type "c:\windows\regedit". That is assuming that you have regedit in your Windows directory and that C: is your master drive. Then click on HKEY_CLASSES_ROOT and then "Find" in the "Edit" menu. In this case you type in "Recycle Bin". Then "Default" is highlighted so you 2x click on that and then just edit the name to be what you want.