Choose specific access point in a multiple access point WIFI network sharing SSID

You can do this in NetSetMan: http://www.netsetman.com/en/wifi The software is free for personal use.

Main menu -> Tools > NSM WiFi Management

Choose the AP you'd like to use and connect.

If you open network sharing center, then click on the picture for your active wireless network it should come up with a window called "set network properties". At the bottom of the window is a button for "merge or delete network locations". After you are disconnected from the network, you can delete the bad AP from this list. It will not connect to that AP again.

Well, I don't know of a free utility, but from what I've gleaned (no personal experience, so YMMV) WirelessMon (USD 24) allows a user to connect to a specific access point within a network containing multiple devices all within a single SSID.