Un plug all Wired Connection and then Plug in then Connect and restart the Computer..Then check the Ping for your connection.If the same problem occurs please call the service provider..Inform the lag details.
You can check the Ping of the Internet Connection easily...To check Local LAN Connection Ping by using the Following method
GO to start->run->cmd->Ping ip-address
or you need to check Ping for website from your computer means you can reach here
Whoisxy.com and do the Ping test for yahoo,Google etc...