Windows 7 - Remote Desktop Connection for Mac (Windows 7)

I use a Macbook laptop with Snow Leopard and an HP desktop running Windows 7 Professional. I'd like to be able to control the pc from the Mac using Remote Desktop Connection for Mac.
I've set up the pc as outlined in this forum and downoaded RDC onto the Mac. When I initiate RDC on the Mac, it asks for user name and password, and automatically plugs in the domain.
My pc doesn't have a user name or password, but if I leave those fields blank I get a message "Try again. The credentials that were used to connect are incorrect."
Can anyone help me out here?
Thanks.

You must have a password in order to connect via Remote Desktop, Your user name "should" be what your name is on the Start menu. Create a password in the User Account Control Panel, (Click on your display picture in the start menu for a shortcut) and then try connecting.

P.S. You might want to clear the domain field of whatever is listed if you are part of a workgroup.

This is a home environment correct?