i honestly dont know how much help this will be but i have XP too so,
when the game freazes up for me i just click the window a bunch of times, until the not responding appears, then click a few more times and it will unfreaze,
also when it freazes up in a loading screen you can do the same thing and it works, but somtimes cosing the window down to the toolbar will make it load, so it will be loaded when the window opens back up, but the third thing for loading screen freaze i have to do somtimes, is do the clicking thing, then i have to click the very top of the window, and the loading bar goes further up with every click at the top...its weird but it works for me..