1. Click start button.
2. Type in search box: secpol.msc
3. Run as administrator.
4. Select Account Policies from the menu on the right.
5. Open Password Policy.
6. Double-click Maximum password age.
7. By default it is 42 days. You can choose a value between 1 and 999 days.
8. If you set the value to zero, password will never expire.