That is why I was saying you choose that option after you change the password and connect with your PC. Logic says that the option will only prevent new devices so your PC that is already connected won't be an issue.
If that doesn't work then I suggest you use the highest encryption you can. What you want is WPA2 (also known as WPA2-PSK). WEP isn't secure at all and can be easily cracked. Unless your computer and other device can't use WPA2 then there is no reason to not use it.

In reality you should only use WPA2 and if you have any devices that can't use it then you should upgrade them so this isn't an issue. I know that isn't always practical so I'm trying to give advice that you can work with right now.

Let me know if you can use WPA2 and choose AES if available.
Evan