Sure, just put that card in the pci slot, hook up the power cables (if it doesn't draw power from the motherboard directly) and do a quick google search for gpu drivers.
Well, you increase the chance of your pc BSOD-ing (blue screen of death) by 80% (if you run games/heavy gpu related applications), if you had a spare older gpu, i'd put that in your pc for the moment.
Well kamidori ain't exactly demanding, it's pictures + text. EDIT: C&C Gen is possible, but 9/10 you fuck up your pc running gammes/apps without gpu. Do you use progs like 3D Analyzer or something?
http://media.giantbomb.com/uploads/4/49342/1774421-sengoku_rance___package_large.jpg
Fuck hot girls, conquer nations, what more do you want? Oh did i mention he's a complete badass.