When a user has forgotten their password and they have not configured Single Sign On, perform the following.
The person carrying out these instructions will need an admin style permission.
There are two ways to get to the user accounts from the left menu bar:
Modules > Setup > System Users
Others, then selecting User Account from the Type
Select the user you wish to reset the password for then click View
Click the Change button
Type in the new password into both boxes and click Save
If not ticked, you can tick the Send account details to email which will send the credentials to the user.