We have just taken over for a customer who has a Vigor 2800, one of my guys changed the password and is unable to get back in, he either mis typed it twice or did something else ... I still access to the router on the server, however, we dont know the old password to set a new one. Is there a way round it other than trahs the router and start again?

How can you access the router from the server if you don't know the password ?

it was already logged in on site, we are trying to access it remotely... thanks for the response but I really could do with the answer not more questions?

If password is saved in the browser on the PC where you have access to it:
mozilla/firefox can display stored passwords.
For IE there are 3rd party programs availible which will show you the password.

If you cannot use this method, but, the password is saved by another unknown method, use a network traffic watch tool like wireshark to capture the traffic - 2800 does not use https so the password will be sent in clear text.

If you were able to login to the router, because the session was still valid, but the password is not saved on the PC, you have to reset the router to default settings, and start from scratch.

Save the router config and you'll find the admin password is probably in it in plain text