Unable to change password

Hello
Either you set a password that complies with the security rules, or you change the rules. To do this, type 'strategy' in the Windows search box. Open 'Local Security Policy'.
Then go to 'Account Policies' > 'Password Policy' > and there you can modify the password settings. Set 'Disabled' for the line "the password must meet complexity requirements".
Then try to change your password again, keep us updated ;)
My configuration:
ASUS ROG RAMPAGE III EXTREM
Intel Core i7 980x OC 4 GHz STABLE 24/7
NOCTUA NHC14
8GB DDR3 G SKILL SNIPER 1600 MHz
SSD OCZ AGILITY III 2X120GB RAID0
SLI GTX 560ti OC 950MHz
NZXT PHANTOM WHITE

Thank you for your replies, unfortunately I cannot change the security rules. Moreover, I don't know where the problem comes from. Originally my password is P@ssw0rd2, I would like to remove the 2.

Hello,
The issue (perhaps) is that the new password is too similar to the old one.

You gave up xD, thanks anyway for your answers^^.