messenger problem

[steve.uk]

i have just installed the most recent updates to windows messenger from the
windows update website and now it doesn't work.

the first thing that happened was when a limited user logged a message
popped up saying that the installation failed.

when i try to sign in as administrator it is asking me for my password(which
it is supposed to remember because i can't.

how can i uninstall messenger, or the update and repair it?

thanks.