There's usually a small "power board" in them, it sounds like you may have fried that.
Probably cost around £30-40 for the part if it is that, and labour costs on top, so maybe £70/80 at a guess?
I can't really recommend anyone mind, but I had something similar happen a number of years back and that was basically the problem, wouldn't switch on etc.
ALWAYS use surge protectors though, they really are a bit of a life saver with things like that and a very sensible investment!