Trouble-shooting Computer with No Internet

The initial questions to ask, when trouble-shooting a single computer with no internet are as follows:

1. Does the PC have a network connection, wired or wireless?- if not, check the patching to this computer, or if others can connect wirelessly try rebooting the wireless access point.
2. Does the PC have an IP address of the correct type, and if so, is this set manually or by DHCP?- At this point you can try disabling, and then enabling the network adapter on the computers Device Manager.  If still not working then try uninstalling the network card and then scanning for hardware changes to pick it back up.  Do not delete the drivers when uninstalling.- If the IP address is different to that expected, check the patching of the PC (does it connect to the correct connection or go through a router?).  Rebooting switches or routers which this connects through are possibilities at this stage.
3. Can the PC ping the gateway?
4. Can the PC ping an external website, eg google.co.uk or bbc.co.uk?
5. Can the PC ping an external website by its IP?- Try entering ipconfig /flushdns in the command prompt window and then reboot the PC.