Remote Drive Access Permissions

I am trying to remotely access drives from my one computer to my laptop in order to transfer files with more ease than running back and forth, burning, copying, etc. The method I am using is simple enough. The drives are set for administrative share [c$, d$, etc]. And I am accessing through the run command via \REMOTE_IPc$. I am definately pinging the computer correctly because a dialog box opens, however this is where the problem begins. The dialog box does not let me switch to an administrative account. It only shows "Guest" in the login name.

I dont have the guest account even activated on my main Desktop CPU and I wont have much access without administative rights. I was just wondering what could be making it so that I cant login under my main administative name. My desktop is using WinXP pro. Laptop is using XP home. Not sure if this fact matters but the desktop is using internet connection sharing that is feeding a router, which in turn is giving wireless internet to my home network wherein my laptop is connected. Also, I can access remote desktop easily enough but even with disk drives shared they do not show up on the remote computers "My Computer" folder.