Thanks for your quick response.
The Realtek adapter is chipset 8191 also states IEEE802.11N on the adapter
When I first plug it in it connects showing 100% strength and 100% link quality. It then disconnects.
Some times it will reconnect and again disconnect.
A box on the task bar then states Unable to Connect to Preferred Network.
There are no other devices connected to the router although my new laptop Dell Inspiron 15r is connected by wireless.
I am trying to use my old Inspiron 8200 in another part of the house although at the moment they are in the same room until I solve the connection problems.