wut? you mean you just bought your new rig and it doesn't have an integrated audio? you must've been scammed.
Lrn2read, man.
the point of the question is if you had your new rig in why'd you even do much with the old one?
though i do understand to not throw it away and use it as some sort of backup rig like i do.
anyway there is alot of PCI audio cards here and there around my area, no idea on yours.
though i suggest you go with these
http://www.usbgear.com/USB-Speakers.html, just plug it and it'll do the rest, well some needs manual driver installations.
yea sure there are drive docking stations that can be bought, i mean something like a plug port for HDDs, though i might suggest you take 3.5 to dual 2.5 bay converters if you plan to put in laptop HDDs in.

but however, the thing you're searching for might be an "external drive bay" or more like a "harddrive enclosure" but usually these have a built in SATA-to-eSATA/USB converters in it.