Be sure you give all users the task rights to 'change password"; before making this change.  The next time the user logs in, they will receive a message "the password on your account has expired or does not meet the security requirements established by your system administrator.  Do you want to change your password now?".  
If they answer no, the login screen clears and they can not log into Sage 100.
if they answer yes, and have security to change their password, they are taken to the Change Password Screen.  

Oh one other thing what is the requirments for strong password... I assume Upper Lower greater that 8 number.. special characters?? 

Press "F1" on the keyboard for the Help File related to that field.

Require all User Passwords to be System Defined Strong Passwords

Select this check box to require that all passwords be "strong" passwords as defined by the system. Clear this check box if you do not require strong passwords.

Strong passwords have the following characteristics:

• Contain at least eight characters

• Include a combination of letters and numbers

• Do not contain repeating characters

Press "F1" on the keyboard for the Help File related to that field.

Require all User Passwords to be System Defined Strong Passwords

Select this check box to require that all passwords be "strong" passwords as defined by the system. Clear this check box if you do not require strong passwords.

Strong passwords have the following characteristics:

• Contain at least eight characters

• Include a combination of letters and numbers

• Do not contain repeating characters

Awesome thanks a tone..