I am assuming the password is not a BIOS password but the initial login password. Make sure you are trying to login under the correct user ID. If this is in an office environment, your system admin should have the tools to reset the password for you if it was forgotten. From experience with users in the past I tell them never change their password on a Friday. The reason is they will sometimes forget it over the weekend if they are not forced to use it right away for a few days.