Allright, problem solved! I used another power cable, and now my Nec DVD burner works like it should!
(im so happy)
glc, i made a photo of the label (PSU), It says Component Pro, it came along with tha A-Open case. :
DSC01895 (Small).JPG Since now everything (still?) works fine, I'm not planning a new PSU or anything.
Thanks for the help, it seems so simple but i wouldn have found it without the help.