Problems with Vanguard

So as an impulse I decided to buy and digitally download Vanguard: Saga of Heroes last weekend. And that was my whole weekend. Had to download over 10 gigs twice due to corrupt files or downloading issues only to find after the patching process I'd have to defragment my HD before I could have a prayer of it working. Which of course after it did, but only barely. It's so incredibly laggy it's unplayable. I'm very disappointed because although my system is certainly on the low performance side it's still well within the minimum requirements, save for the sound card perhaps, but at this point upgrading it just to play Vanguard seems like sending good money after bad. =(