What Snyder said is absolutely correct but another idea is to check your anti virus tool. You can look in this thread
to get an overview of the problem and help, too.
Do you have already installed (or tried out) the patch v1.3.3? This patch fixes some problems. If you do not own the american or russian version you have to be able to install this patch and should do this.
Additional to that it's very helpful to have more information about your system at all.
Bis denne, Han Solo