Windows 7 Help with networking

Hey everyone, new here, and hope someone out here can help me. I am trying to set up sharing files between me trusty old x-box (not a 360, but chiped) and my windows7 pc. used to work great, but since my hd crshed and i had to replace it it doesn't. have selected the folders i want to share on my homegroup, set the permissions, disabled password protected sharing, set up norton 360 with correct ip address of x-box. when i start the mediacenter of the x-box it sees my pc and all the folders that i want to share, but still asked me for username and password. Also i can't switch on network discovery. its always turned off. if i switch it on and select save, the window just closes and discovery is again selected as off.
Does anyone have any idea???