crashes/lags in towns

Describe the problem. Be as specific as possible!:

When im in any town it lags like hell and crashes but only when im in a town.
anyone got a solution to this problem because i cant play

edit:
i have now tried both on my vista and xp and niether is working

 Images of problem

its like a screenshot

I get the exact same problem, it's especially bad near the middle of towns, the edges are usually fine.

I get the exact same problem, it's especially bad near the middle of towns, the edges are usually fine.

exactly the same