Constant wifi problems, but only on my Mac

[tekno]

My O2 wifi has worked fine for over a year. Suddenly in the last few weeks I'm getting constant "Safari is not connected to the internet", "A connection timeout occured", pages just hanging when trying to load and, at the moment, I simply can't connect at all (I'm using my mobile internet).

Oddly though, my Samsung S2 is having no problems at all. This makes me think the issue is my Mac - unless there's some other reason it might only affect my MacBook Air?

Any help on how to work out where the issue is would be greatly appreciated.

 

[blatopilot]

Try restarting and holding SHIFT before it boots (Safe boot)....Things will be slower, but is there any difference? That can help isolate if its a 3rd party app as a first step.