On the Windows 7 Peer to Peer File Server:

1) make sure the file server is a WORK network

2) show network map

3) registry keys

set the following registry key to ‘1' 
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache

and set the following registry key to ‘3':
HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size

On the Windows 7 clients:

4) registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\NetCache
set the SilentForcedAutoReconnect DWORD to 1

5) check the network map
go to Network and Sharing Center | click See Full Map