password help

During installing Ubuntu server 8.04 on vmware server i had a frozen screen near end of install did restart selected repair installation ran through finished
rebooted but it does not except my user name and password.

Is there a default password to get me back in or do i have to start again??

Any help would be great as i have wasted 5 hours on this already and got no were.

Cant you login to single-user mode, from there you can either, su into root, perhaps blank password, sudo a command if a member of "wheel" group and run passwd root and set a new password for the account.

I've found during failed installs it generally resets using a blank password "even if the installer enforces a password" you can still blank it.