To my understanding there aren't "converter" cards for using a PCI-E card in a PCI slot. If there are, I wouldn't recommend them. Also, for the most part such "converters" would require that the card be low profile (because the card you are installing will in fact be plugging into the top of the adapter card). The Titanium HD is not even close to being low profile.
Basically, yes, you will need a whole new motherboard. Ideally you'd be able to take it back and get a PCI card; my X-Fi card, for example, is PCI, as are most of my sound cards, I'd like a PCI-E one though since I have lots of empty slots
, wanna trade?
.
Chances are, if your computer doesn't have PCI-E slots, then it's a tad older and it's unlikely you would be able to use the card to it's full potential.
P.S: in the future it is best to research what you have,need, and can use, before making a purchase for peripherals
