Vista - Unidentified Network (Public Network)

Heyy i got some error when i wana connect to the internet using my other computer i got 2 computers 1 with the internet modem in (my sisters room) and the 1 in (my room) connecting to the internet through from my (sisters computer) my sisters computer has her internet running as i speak im using it.. but when i click "network and sharing center" i got (Unidentified Network (Public Network)) can anyone please help? im using a Realtek RTL8168B/8111B Family PCI-E Gigabit Ethernet NIC (NDIS 6.0) network card. so only my network is working with no internet my internet in (my room) used to work, but seems like when i changed xp to vista 32bit help plz thanks everyone

You dont happen to be running AVG 8 are you? Seems like there are some cases where it is causing problems with the network stack that Vista uses. I have found it to be the culprit on my Vista Ultimate x64 system but on my Vista Home Basic x64 laptop it has no problems (granted I am using wireless connection for the laptop and wired for the desktop).