Trawling the archives I've seen similar but not exactly this so here is my problem and if anyone knows anything I'd be grateful for advice: I have 3 machines on my LAN and I have a PPPoA broadband connection using a Netgear DG814 ethernet modem/router. I use DHCP to set the public (static) ip and private ip (192.168.0.2) on my main machine and fix the others at 0.3 and 0.4 - previously my OS was XP Pro and all was fine. I have changed to Vista Ultimate. Now, all is still fine for at least 2 days uptime but at some random point after that I get a problem. Firstly I cannot browse or get emails but I run a server that takes external connections and any pre-existing stay connected and data is still transferred. So I have an internet connection it seems of some sort but I cannot ping DNS servers. I can ping my machines on the LAN but cannot connect to any (eg telnet to a server on port 23 or 21). I cannot access the setup page of the modem on 192.168.0.1 either. Secondly, after a while the situation worsens as ping fails as well. The only solution I've found is to reboot the computer - I don't need to restart the modem. Clearly Vista is the issue because I can pinpoint the start to when I first changed to this OS. A google search reveals an increasing number of similar stories day by day as the take up of Vista increases but I've not seen any solutions. So if anyone on here has one, please let me know.

Correct me on this if i am wrong. I think by default windows firewall is enabled in windows vista. Try disable that see if it helps.

It is enabled by default only on inbound connections. In any case turning it off does not help.