Why is XP versus Vista being discussed on a forum for a Vista-only program. Aside from the fact that anyone my age 30+ will remember the "XP suxors, I'm sticking with '98 because it supports more programs" arguments.
Fact: 1GB of Ram is barely enough to support Vista, much less a development environment inside Vista.
Fact: Your video card is considered a high-end "consumer-card". Where as, a GTX is considered a low-end "developer-card".
-resolve these issues & your problems will severely decrease-
break it to make it.