Ando:
Although hard drives are platform universal, PCI cards are not. You need a card that's specifically designed to work with Macs. It appears fom the specs on the site you referenced that the card you bought is for PCs (requires Windows).
I'd return it and get
this one from Sonnet,
this one from Acard, or
this one from SIIG, since you opted for ATA versus SATA and purchased an ATA hard drive.
On an MDD Mac, set the jumpers on all of your hard drives to cable select and the computer should recognize them all aprropriately, regardless of the controller they're on. Also, when you have a single drive on a ribbon cable, it's good practice to connect it to the end connector of the cable to prevent fringe signal interference (which could cause drive data corruption).
The flashing question mark appears when the Mac does not "see" an OS to boot from. After an internal hardware addition, it's a good idea to
reset PRAM to "retrain" the Mac where to look for the drives and other hardware (PCI cards, AGP video card, etc).
Gary
1GHz DP G4 Quicksilver 2002, 400MHz B&W rev.2 G3, Mac SE30 Mac OS X (10.4.5) 5G iPod, Epson 2200 & R300 & LW Select 360 Printers, Epson 3200 Scanner