In reply to:
no the first set were just into the master socket which does have extensions around the house but none of them work for internet is that normal for a new house?
Sounds like builders' wiring, in which case that could make your line very noisy, as well as stopping the other sockets working with ADSL. Take a look at the wiring guide
here, then physically check each socket.
In reply to:
only the phone works in them there is 3 extensions built in.
That does make me think the wiring is at the heart of your problem. There's a strong chance it's been done badly and, while it will work for voice, it's just putting so much noise on the line that it's stopping ADSL from working. If you don't feel comfortable re-wiring yourself, you may need to get BT out.
In reply to:
so how can the power supply be interfering with the phone line?
Most electrical devices emit some noise. Power supplies can emit a lot. If your noise magin is low, then the extra noise can be enough to kill the ADSL signal, the modem becomes unable to distinguish it from all the other noise on the line. It's worth trying to keep power cables away from phone cables as much as possible.
In reply to:
do i have to get bt out to fix that? i was told on some other forums to contact isp but they don't help at all, tried talking to bt before they just say we're not with them as broadband. 3 extensions everything is filtered that needs to be our sky box isn't plugged in because we don't use the internet on there.
If you don't want to tackle the wiring yourself once you've read the guide I linked to (and there are many other guides on the 'net), you need to either get a BT engineer via your ISP, or a local contractor. The reason for going via the ISP is that you get an ADSL-trained specialist, not a voice engineer, which would not help you. Only the ISP can get these engineers out, BTw will not talk to you as you are not a customer of theirs.
It might be worth clarifying that the devices which need filters are the analogue ones, eg phones, faxes, analogue modems, Sky boxes. ADSL equipment does not need filtering, that side of the filter is, in fact, a 'pass through' connection.
HTH