Various errors when connecting to other computers on network using Windows 7

Hi community,
I am receiving this error:
Error code: 0x80070035, the network path was not found
While trying to connect to any other computer (running Windows 7 Ultimate) on my network. I owned another computer with Windows 7 Ultimate, and it does not suffer from this problem. Firewalls are unable to perform on all computers.
Pings are fine on all computers. Ping by name is possible.
While trying to connect via IP address, I receive this error:
Error Code: Error0x80004005 Unspecified error
So please help me with correct suggestions.
Thanks.
