1. Start / Program / Administrative tools / Local Security Policies.
2. Click on 'Account Policies'.
3. Click on 'Password policies'.
4. Double click on the Password length.
5. Specify the character '0' i.e. 'zero'.
6. Apply / OK.
7. Again right click on 'Password must meet complexity'
8. Click on 'Disable'.
9. Click on Apply / OK.