Mouse, modem not working

[Guest]

I recently replaced my motherboard, with a second-hand one. Now my mouse and modem (both connected through the serial ports) don't work. It's like the computer doesn't recognise that they exist, even with the drivers installed etc. The only way I have got a mouse to work was when I was testing it at work with our network guru here. We had it connected through a PC switch, and so the "common" mouse worked, but no mouse worked when connected directly. I wondered if the mouse using the PC switch draws a different level of current than that of a directly-connected mouse, and whether that was making the difference. Apart from that, I have absolutely no ideas. Any suggestions?
The motherboard came from a reliable source, and was driving a mouse just fine when removed from the machine it was in.

 

[ksoth]

Have you checked to make sure the serial ports are not disabled in the BIOS? On my computers, if I don't use a port (serial, parallel, USB), I disable them in the BIOS to free up resources. Maybe the guy you got that motherboard from did the same thing.

"Trying is the first step towards failure."