I finally solved my problems.
The pc started rebooting at random times also after finishing playing DD.
At the end, I thought it should be some hardware prob, as I did not have any virus on my pc.
It came out to be one of my Rams (I do have 2x512 MB) which caused several problems. As soon as I took it out everything started working properly and I did not have random crashes every 5 min. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Thanks for your help and sorry to have thought at once about the program itself...
Have fun <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />