gtrplr.
sometime read my tips in this tips section.
i would also suggest you get a good book on midi.
if your going to be doing lots of midi work.
its pretty essential.
zzounds.com and music123.com have a slew of devices to connect your mackie mixer
to a computer.
and digitise audio if doing audio trak recording,
plus midi devices.

rather than useing on board sound chips in laptops.
an inexpensive device for audio recording from your mackie would be a toneport gx.
to record guitar traks you dont necessarily need to use your mackie.
just plug a guitar chord into toneport input...select a guitar amp/cab/effect n record.
the gx has lots of guitar tones built in.
(see line6.com)
i'm rather happy with mine which was a present. its usb.
for midi..pg itself sell a midi to usb device for recording midi traks.
(look under hardware.)

as to detailed working on biab midi traks.
the biab companion product by pg called powertraks will load a biab song and let you work on it further.
loads of midi traks...up to 48.
the advantage is by useing powertraks all your biab settings will be imported into powertraks.

ps...lol.i was an old tape guy once. 2 inch.

retired puter engr....powertracks on amd......NICE !
"what is the black art of audio engineering ?"
my silly songs...motagator.com/bmanning
see my tips in the tips section.