Left click on "computer", select "manage", select "device manager". Look for any yellow attention symbols. If one appears next to your network adapter, you have a problem. See what it says. If there are no attention symbols, look down the list for the adapter and click on it to look at "properties". One of the tabs will say "this device is working properly", (or not). If not, try the "uninstall" option, then right click and "search for hardware changes". The device you deleted will then re-install.
After his look at "network" and look for your adapter.
Have a fiddle with it until you work it out. Swot I did!
Good luck!