At a minimum you should be posting this info...
When posting a problem, be sure to include the following information about your computer:
Operating system (Windows users: be sure to mention if you have XP or Vista, and which Service Pack you have)
Video/Graphics card type + graphics memory
RAM (random access memory)
If you have installed mods, search or post a topic in this forum
This will help us to identify the problem.
Be sure to have a glance through our oh-so-useful Buglist, complete with multiple solutions to well-known recurring problems.
When I start on PC (XP anyway)-- it is NOT windowed????????