My sound card has numerous inputs: spdif, aux, mic, line... Is it possible to record from all these simultaneously on separate tracks?

The multiple input that you refer to are in practice input to the soundcard's analog input mixer, that mixes all this input in to a single signal that is given as the imput to the soundcard's only analog to digital converter, so you all the inputs can only end up in the same track. I'm not sure about the SPDIF input: being it already digital it may be possible that the soundcard can record simultaneously from it and from the A/D converter, but I doubt that this has been implemented. If you can see only one entry in the Preferences/wave devices dialog box (apart from WAVE_MAPPER), you can only record one track at a time (or two mono tracks, if you can feed two separate analog inputs in the soundcard's line-in, for example connecting two mics to an external mixer and connecting the mixer to the soundcard). Of course there exist soundcards that have multiple A/D, such as the GadgetLabs Wave/4, which for example having four inputs is seen by Windows as 2 stereo standard soundcards. 3 - ...  more