I'm sorry, but you're going to have to give us a little bit more information here: What type of modem, DSL, Cable, Dial-up? Does your computer receive a valid IP address from DHCP? Is the modem/ISP even supporting DHCP? If it's a cable modem have you tried contacting your ISP? Some cable services require MAC registration before you can connect. If it's DSL have you installed your ISP's connection software or manually configured the PPoE connection? What are the results of an IPCONFIG /ALL? Please post them here.

my laptop connects to a modem but not LAN and refuses to activativate saying that there is no DNS server....

Hi, As Bob sail, more information is needed for troubleshooting. Click Start, input cmd, in the window, input the command: ipconfig /all What's the result? In addition, try to flush your DNS and register it to check if it works. Regards, Miya This posting is provided "AS IS" with no warranties, and confers no rights. | Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.