Windows 8 Internet Issue

Hi, just bought a sony vaio duo 11.

Internet worked fine for a month then decided to stop working for 2 days, decided to work the next and has now stopped working again.

It appears as it is connected to the network i.e. full signal bars buur when you try and open any app that uses the net there appears to be no connection.

Computer came preinstalled with Win 8 so not upgraded.

Fairly new to this so not sure what information is pertinent to resolve this query.

Any help would be much appreciated or its going back to Sony!

Thanks