I couldn't get my XP to connect to my Windows 7 until I tried the following sequence:
My Network Places/
View Workgroup Computers/
(right click on computer name) Open/
(same for) Users/
I had previously shared the folder, the My Documents and the Drive but none of those let me in directly until I did the above. Good luck. I've been working on this since 10 this morning and it's now 5:30; that's seven and a half hours.