If you mean you can't access shared LAN disks,

1. Open Windows Live OneCare.

2. On the Windows Live OneCare screen, click "View and Change settings" on
the left hand side.

3. In the Windows Live OneCare Settings dialog box, click the Firewall tab
and choose "Advanced Settings".

4. Click on the Advanced Tab. For the option "If my files and printers are
shared", choose "Only share them with computers on my local network
(subnet)".
For the option "Allow Remote Desktop Connections to this computer", choose
the option "Only computers on my local network (subnet)."

5. Click on the "Ports and Protocols" tab, put a checkmark in front of
"ICMPv4 inbound" and "ICMP outbound". .

6. Click OK.