One admin account for desktop/laptop access

I recently purchased a desktop from a friend and am trying to figure out what the best way to configure 1 user account for each would be.

WHAT I'M LOOKING FOR: A way to easily control the items on my desktop from my laptop and vice-versa. Not through a Remote Connection, just a way to avoid the "You must have permission from \\User-Laptop\User. Contact Network Admin."

I've already set up shared folders on both systems, including making a shared folder for both C and D drives on each machine. This, however, suddenly stop working and began giving me "Access is denied" errors.

Any Suggestions???

P.S. Both machines are running Win 7 Home Premium x64