FYI: When you ask questions here on LQ, it is very helpful if you tell us what distro you are using, and what version of said distro.
Are you using Ubuntu? If so, then what version?
I assume you are using Ubuntu since you said you only have one password (i.e., no separate user and root passwords as in most other distros). If you are using Ubuntu, then read on for a possible solution:
If you disable the automatic login, this problem will go away.
If you feel you must have the auto login, then follow the advice given in response #1 here: https://answers.launchpad.net/ubuntu...uestion/149677
An alternative solution is posted here: http://askubuntu.com/questions/867/h...eyring-on-boot
Write back if you need more help.
EDIT: If you have forgotten your password in Ubuntu, see this to reset the password: http://psychocats.net/ubuntu/resetpassword
And welcome to the LQ forums!