connection problems

After problems with slow speeds on Tiscali my mum switched to Plusnet. All was OK when she switched but now a few days later she can't get connected.
She is running a windows XP machine a speedtouch 330 modem.
She is on the Bideford exchange
When she trys to logon it says username/password not recognised.
There is a green light on the modem saying it has synched OK.
Plusnet have been unsupportive saying it must be a modem issue.
Have so far tried:
1. Uninstall speedtouch software and reinstall.
2. Uninstall software and install another speedtouch 330 I sent her which I tested and works on my line.
3. Tried logging on using the test account bt_test@startup_domain
4. tried removing all other phones in the house.
5. tried swapping the ADSL filter for another one.

Any suggestions? I thought the synch light meant she still had an ADSL connection but then why doesn't the bt_test@startup_domain work?

Is it possible it is a software issue on her PC? She picked up a stand alone BT router so she could go wireless off freecycle. She isn't very sure how to install it and I was going to do it when I visit next month. This is untested but I guess could be used to test the line independent of her PC if I can talk her through the setup.

Have you checked that the correct broadband username is being used? This will be [email protected] - forgetting to add the realm after the @ is a common cause of failure to connect. The password is of course the one assigned to the username.

Have the other parameters been checked (VPI=0, VCI=38, PPPoA and VC Multiplexed)?

Hi there,

With that kind of error, it's really unlikely to be anything at our end.

If you would like to PM me the account details, I'll be more than happy to have a look.