Dropping connection due to IP address release/renew problem

Hi there -- I have an Inspiron 23 Model 5348, connected to a BT Home Hub 5 router running Windows 8.1. Every time I wake the computer up from sleep and often even from booting it up I have no internet connection. I have to release/renew the IP address, and the connection is restored for a while. 

This happens on my inspiron whether wired or wirelessly connected. I have upgraded the router, changed the wires, reinstalled the network device drivers, changed the lease time on the router to 21 days and used a static IP address, bit nothing seems to work. 

It only happens on the Inspiron. None of my other devices drop their connection.

Any ideas what is causing this??