gunfighter claims this works on early 350s and 450s
Try This,
Power off , wait about 30 seconds, Power on...
Within 15 seconds type : NetICs<cr>
You will then be in enable mode... You should be able to retrieve the password from the security menu.
(that is an eye in NetICs not an ell)
dtjsubs offers this for the 450s: This is what I have done in the past. Place the switch (with the unknown password) in a stack with a Switch You DO have the password for, Making the 'known password switch' the 'master' (this controlled by a selector on the cascade module). Then reset the whole stack to Default Settings, this will remove the unknown password and all your config also! So you will have to rebuild your Config.
Frid4y says "The "new" versions I believe require the same thing as the 450 switches, which is call tech support and give them your MAC address for them to create a password."
Hope one of the first two works for you so you don't have to go to Nortel, if not, it is a minor fee..
I tried to remain child-like, all I acheived was childish.