Emergency problem

[George E Noon]

I am really stumped!
I really never thought I would have this sort of problem with my Ubuntu
Linux Computer.
I now have no way to input numerical characters at all, except in the
Thunderbird Compose window, for some odd reason.
I am about in a panic, which doesn't help, I know. I can not shut down &
restart, because my username is composed partly of numerical characters;
no, I have not tried restarting yet --- but I did try running Update Manager,
which, of course would require entering the superuser password; no matter what
I tried --- caps lock  on, caps lock off, caps lock on + shift, caps lock  off + 
shift --- no numericals!!!
This means if the computer goes down, for any reason, I can not get to the
desktop without a complete new install.
Please - does anyone have an idea for a fix.
I have also tried two keyboards --- no change.						
George E Noon