Check your network cable phyical connection. Expect to see lights around or near the connection to indicate activity and power
usually you will see two lights - one for power and one for network traffic (which will blink when active)
If you don't see any lights this may indicate a problem with the network cable or your machine's hardware (the NIC). Try using a different machine and/or network cable.
If wireless try moving closer to the Wireless Access Point. Or even better, plug in a network cable into your machine.
Check that your internet connection is down
Run a few different internet applications to check that it's across the board (eg inetner explorer and outlook express send/receive).
start > Run > “cmd” enter > type “ping google.com”
If you see replies then your internet is fine and the problem lies elsewhere
start > Run > “cmd” enter > type “ipconfig /flushdns”
Easier just to reboot your machine
Check the link light on your modem/router
If the link light is off then contact your Internet Service Provider
Power Cycle your router
In other words pull out the power chord and plug it back in again
Do not press the reset button as this may wipe the settings of the device
Check the phone line (plug in a phone to see if you get a dial tone)
Contact your ISP (request a line test), they will also tell you if you have been naughty and not paid your bill
Remove any devices that share the phone line (including line filters)
Try using a different router/modem
A new device will require configuring so please do not do this unless have done this before