Couple of things to consider:
1-with the old(Mac?) system; does it have HD software with license? If it DOES, remove the 003 and pick up an old 888 interface or go lightpipe with a Behringer ADA8200. If it does NOT, then maybe skip the cards, connect the 003 and try installing LE7.x??? Or, grab an old Mbox "original"(probably costs $25 now).
2-those old sessions might be saved in SD II file format and no Windows rig is going to read those AFAIK(best if you can open on a Mac setup and Save Copy>change format to wave or AIFF>check the box to Enforce PC/Mac compatibility(those copy sessions SHOULD open on any current rig)
3-I suspect working out #1 might be your best bet to retrieve the old sessions. When I had my Nashville room, I kept an old G4/Mbox in a closet for just this scenario
