Steam Bad Company 2 connection problem

So heres the problem.
I built my SB system at xmas, and Im really keen to see how much beneft my quad has over a dual core CPU.
The game worked fine on my XP64 OS, but now Im on W7 its not cooperating.
I log into steam without problems. All my other games connect without a hitch. Except bad company 2.
It worked the first time I connected to a server, but now it refuses to work. Whether I go via server browser or game finder I get the same message,
"connection to the server has been lost, please check your network connection and try again".

Ive checked my connection Ping 37, DL 17mb, UL 0.5mb.
Ive googled the problem and people have said a variety of things.
Disable upnp - Didnt work.
Port forwarding - Didnt work
Punkbuster update - Didnt work

Im at a loss.
Anyone had this problem and fix it? What did you do?

 

I had to enable a little thing in my router called DMZ

 

There aint a chance in hell Im doing that.

 

This problem comes and goes for me, but I haven't been able to connect for over a month and a half. EA support is utterly useless, as they constantly blame my end of things despite the fact that everything else works flawlessly, and that suddenly I'll be able to connect without changing anything.

 

When you log in enter a wrong password a few times, then log in as normal. I had this problem months ago, in the end just had it never save my password and I put it in each time.
EA Support are terrible.

 

What router are you using?

 

I used to have almost this problem, only for me it would happen every round and a half, without fail. I could join a game, finish that round, then halfway through the next one it would error out. I fixed it by moving house and being on BT Infinity instead of o2 broadband. I realise this probably doesn't help...

 

Netgear DG834Gv5.

Ive just spoken to Virgin who told me that its an issue with steam being recognised as P2P services, which is a pile of crap beacuse ALL of my other games work flawlessly.

Were planning to move in 18 months/2 years- our end of the street only gets ADSL (but the other end can have fiber optic).
Me and the Mrs have both said that the deal breaker when looking for a new place will be- "Can we get a fiber optic connection"?

Really pissing me off