if you forgot your password.
just try to boot in single user mode
1) boot -s
2) it will prompt Enter pathname of shell or RETURN for sh: just press enter
3) fsck -p / && mount -uw /
4) fsck -p /usr && mount /usr
5) passwd
type your password and this time dont forget what you haved type
6) reboot
ref:
http://openbsd.org/faq/faq8.html#LostPW
it will work if you havent created a password for single user mode or you didn't forget your password in single user mode..
