I have 4 PCIe serial ports, 1-4. Recently, one of them stopped working. According to the Device Manager, a "Communications Port," not serial port, was assigned to the same port number. I removed it, but it returned after a reboot. Changing the port assignment to a different number solved the problem, and does not seem to have broken anything. It was not there with any port number before. I seldom use those ports, so I don't know exactly when it appeared, and am curious what it is.

The device manager gives "Standard Port Type" "On PCI Standard ISA bridge" with a MS driver. The mobo is an 890GX Extreme4, AMD Phenom II 6X, and the OS is WIN7 Pro 32 bit.