Cannot find server or DNS error

Hi, I've got a home network runing ms sbs , everything's been working fine until now,now when i try to connect to net i get the error "The page can not be displayed and Cannot find server or DNS error at the bottom.I haven't changed anything.where can i start from to figure out the problem,Ive checked the line and its fine.

I can help a bit more if you give us some more details about your setup, but it appears to be a DNS error. Check that your DNS settings (on your SBS server or router have not been altered) It could also point to a problem with your ISP's DNS servers. Have you tried accessing websites by directly typing in IP addresses. Try "207.46.198.30" for www.microsoft.com or 66.102.9.99 for www.google.com . If those don't work then give us some more details about your setup.

I've tried doing that with no luck,I can not even get emails that use pop.I've got a diginet line that goes to the csu which is connected to a cisco 800 series router that is connected to a switch,the sms 2003 server which is also a dns server connets to the switch and clients connect to an ap ,clients have static ip addresses.the lan is working fine

Could you post the output of "tracert 64.233.167.99" (you can censor some octects of your network's IP addresses)?

please try to use the cisco router to do a ping using ip address and hostname to external address i.e. www.microsoft.com . If the ping is successful it means the point before cisco i.e. sbs server might have issue. Then post more info so we in this forum could help on troubleshoot further ...

I finaly sorted the problem,there was a prblem with the csu,when it was replaced everything worked fine again,
Thx