Did you mean 870? 780 doesn't show up in a google search
The 780 comes with Windows 7 and that will not work(even if the card fits). You need Windows XP(probably impossible to find and completely unsupported). Then you need a PCI slot(not PCIe) which does exist on certain versions of the 870, and you also need Pro Tools LE software version 6.4 or older(again, gonna be tough to get).
Just an opinion, but if you want to run Pro Tools, its time to up your game to a modern computer and much newer software, all around(I would not suggest Pro Tools 9 or older, stick with 10 and newer). If you just need to record on the cheap, grab any current(and inexpensive) interface that suits your IO needs and get Reaper(its free to try and cheap to buy) or grab Pro Tools First(also free but limited, but does require an iLok 2/3). Food for thought