Just had windows 7 installed.............

you need to install directx, I think if you leave bf poker alone long enough it will start the install for you

Common problem this.....I had the same a couple of years back with my then new lappy which runs vista.
Not sure it's as easy as M says to sort out but I may be wrong. I remember installing direct X and that still didn't work.
I ended up taking my laptop into work to let one of the IT lads sort it.
Thought betfair would have sorted this by now to be fair.