Like the title says... I have multiple PCs connected to a switch, I have a wireless access point that has been connected and working to the switch for a while, suddenly the network crashes. I isolated it to the wireless AP that when plugged in, nothing is accessible on the network, when I unplug it then everything works. It's almost like the AP is flooding the network rendering every other network component inaccessible.
First thing to try is to backup or make note of the settings on the AP. After doing so, reset it to factory defaults and see if it still crashes the network. If not, it's most likely a bad config. If the network still crashes, you could have defective hardware. If it appears to be config related, we can start troubleshooting that, but will need a bit more information about how the network is setup.