Acer Altos 11000 System User Manual page 82

The Base Address and IRQ parameters are
configurable only if Parallel Port is enabled.
If you install an add-on card that has a
parallel port whose address conflicts with the
onboard parallel port, the system
automatically disables the onboard functions.
Check the parallel port address on the add-
on card and change the address to one that
does not conflict.
3-26 User' s Guide