Cannot record from mic or line in.

I have a Gigabyte GA7ZX motherboard with 800mhz Duron processor,
256ram. My sound card went bad and I installed a SB 16 PCi and also
installed WinXP Home. Found out that the sound card was not supported
by XP. Tried a Diamond DT-688 which was supposed to work but didn't.
Installed Philips Sonic Edge which is supposed to be compatible with
XP. System sounds and CD's play ok. I still can't record with either
the mic or from line in. I have gone into BIOS and disabled the
onboard sound. I have checked all the volume controls, and nothing is
muted or checked or unchecked where it should be. If I connect a tape
recorder to line in it plays through the computer speakers but it
doesn't record. Could this be a motherboard problem or am I
overlooking something else?