modem prob/cant read port from registry

I installed a video card in a hp pavillion, (4456)366Mhz now my modem will not work.It gives me an error (cannot read port from registry)NO conflict in device manager.It will install on com2, I don’t see a com 3 or 4 available.Did diagnostic, it says cannot communicate w/ modem , make sure its turned on. I’m running ME. Checked bios, only 2 com ports available.Worked fine w/ ME before video card installed.