Possible solutions are known, posted frequently and even included within the EB Install Guide which is stickied. I'm not really in the mood to re-type everything here, especially since -for me- it is shrouded in might's and may not's rather than actual irrefutable fact -- I use Vista and have not experienced anything of the sort at all.

In short: don't install games in your Program Files folder, and don't just let the Installers do whatever they do automatically; review it before pressing OK/Continue.