Wanted to buy it, but demo locks up

[City Builder]

All other games that I play, play splendidly on this computer, and no overclocking here.

I was able to finally play if I skip the intro, the part where you have to go fight the dragon, if I let the guy decide what is my fate then I was able to play the game for a while, however at the same time I turned AF up to 16f and turned off music and adjusted some other settings so it could either be that there is a problem with the intro area and vista 64 or it could be a matter of some settings and what they produce is not good with my computers operating system.

I don't know which it is, but find it unlikely at the moment that Im going to pay full price just to find out that I have problems playing it in the full version.

This is a relatively new computer for me, I just bought it locally about a month and a half ago however, it plays all my games on the highest settings without crashing, I may get some slow downs in frame rate here and there, but no other games that I am currently playing cause the computer to crash yet.