COM port not behaving...

Hi all.

(I had posted this message in the Hardware group earlier; but I see more
activity here so I hope it's OK to put it here too, to increase my chances of
finding a solution.)

I seem to have a stubborn serial port.

I just got a new motherboard, with one onboard serial port, and also have a
PCI expansion card with two serial ports.

After I installed the drivers for the expansion card I got an error message
regarding COM1 (the onboard port). I blamed it on a silly driver conflict,
forgot to write the exact error message down, rebooted the PC, and everything
was fine. Or so I thought...

Yesterday, when I started one of my programs that use all 3 COM ports, I
immediately got a "cannot open port 1" message. After checking the ports and
their settings in the device manager, I saw "this device is working properly"
for all 3 ports. Yet COM1 refused to work. 2 and 3 worked fine.

Blame it on pure luck, for some reason I disabled COM1, and then enabled it
again. And after that it worked. So I didn't investigate further.

This morning I start up my PC, only to find out that COM1 wasn't working
again. "This device is working properly". No, it isn't... So I decided to do
the disable/enable routine again, and sure enough, it worked.

I have gone so far as to uninstall/install COM1 through the device manager,
thinking that that would fix it. After uninstalling and rebooting XP (SP2)
picked up the "new" device, and installed the drivers. But again, the COM
port was not working until I disabled/enabled it.

Does anyone have any idea how I can fix this permanently?

Thanks,

Erik