my wifi connection keeps dropping out and does not reconnect automatically

Every time when I turn my Powerbook on, even if awakened from sleep, or if the internet connection is broken I am unable to reconnect with my BT home hub4 router and gain access to the internet, network preferences tells me that my wifi has no IP address, which clearly it has, as everything else in the house connects to it with no problems whatever.

All was okay until the last update on Maverick

In trying to solve this problem I have removed Thunderbolt Bridge from the list of networks whatever that is and also the file named below which is stored in a file should I need to reinstall it.

com.apple.Bluetooth.phlist

After removing this file I was for a time able to connect ok maybe once or twice but then it all went to pot.

What is particularly galling is that the budget tablet that I got for £42 incl postage has no problems at all and connects merrily all the time.

Many thanks

Macbook Pro 17 inch, late 2011

2.4 GHz Intel Core i7

8GB 1333 MHz DDR3

Intel HD 3000 512 MB

OSX 10.9.5 (13F1077)

I do have Flash installed and it is up to date.