Since you said you've changed the router, then all the connections from that point on will be, can only be, the same type of encryption.
Changing it on the router will "shove" all the old connections off, and they will have to re-establish at the new encryption.
The newest versions of Windows no longer have the need for you to select the type of encryption, it is an automatic type of selection. All you do is select the signal (the SSID broadcasted name, assuming it is being broadcasted) and you enter the passkey. Windows will then figure out what sort of encryption is needed.
My point is, you don't have to tell your computer what sort of encryption to use. You only set the Router, and the rest will disconnect until you re-establish, once you enter the correct passkey. If you've already established communication they you are already using the set Router encryption.