Question : DNS Error - Server cannot be found

Hello,
We had enable vpn on our windows 2003 server , After that server not access from client, Then we had disable vpn but problem is same, If i am accessing the server via server ip, Its working fine & if i am accessing the server via server name(http://sharepoint:41082) its not working. its getting the DNS Error - Server cannot be found. Also if we want to join a client pc to domain (my computer- property- computer Name- change - domain- then type the domain name MYcompanyname.com) its getting another error(the domain control for the domain yourcompanyname.com could not be connected.
Can every body help me . Its really urgent for me.

Regards
Gautam

Answer : DNS Error - Server cannot be found

Thanks for helping me, This has been resolved , This problem is not from dns related, This is a dns setting problem in lan settings,

Again Thanks