Step 1: Go to Start > Administrative Tools > Group Policy Management.
Step 2: Click the Little Arrow on Forest: your domain > Click the Little Arrow on Domains > Click the Little Arrow on your domain > Default Domain Policy.
Step 3: Press Settings then Right Click Inside the Settings Tab and Press Edit.
Step 4: Click the Little Arrow on Computer Configuration > Click the Little Arrow on Policies > Click the Little Arrow on Windows Settings > Click on Security Settings then Double Click Account Policies.
Step 5: Double Click Password Policy then Double Click Password must meet complexity requirements.
Step 6: Click the Disabled Box then Press Apply > OK
Step 7: Open Start > Run > CMD > OK
Step 8: In CMD type gpupdate /force when its done updating the policy, you will be able to set a password to anything you want.