My Network Places

Quite a straightforward problem but one i can’t solve. I can’t access other machines through my network places\entire network without getting error message ‘domain controller cannot be contacted’. However, when i try to access machines through \\servername\sharename i can access with no problems, and for the duration of being logged on. Then, if i restart machine i have to go through this process again. I have enabled NetBIOS over TCP/IP. Any solutions please?