COM1 conflict with Standard PC

I'm trying to use serial port COM1, and the device manager shows an I/O
address conflict with device Standard PC. Sometimes COM2 conflicts with
Standard PC. Sometimes one of the ports is OK.

Any ideas? (I tried /noserialmice in boot.ini, and that didn't help.)

I eventually need to use COM1 for kernel debugging, but for now I'll be
happy to resolve the conflict.

--
Regards.
Mark K Vallevand