Computer #3 does not connect with this router. Computers 1 and 2 are connected fine

Dear Sir of Madam:

I have two computers (Computer 1 and 2)  that are interfacing OK with this router. Computer #3 does not want to connect with this router. When trying to access the internet from Computer 3 the error message says "router requirements are not consistent with what is stored in this computer". In computers 1 and 2 I am using the following Properties: Security: WPA2-Personal, Encryption: AES.

Does anyone have a word of advice to resolve this problem? I am using Windows 7 in all three computers

Thank you

WJS