Using PowerPoint 2010, I was able to view your sample. I can modify your slides', white backgrounds with gradient backgrounds, photo backgrounds and/or solid color backgrounds. Your slides have interesting diagrams, so unless you want these changed, I would not modify them. However, I can animate the diagrams. In addition, I can include page transitions. I do not speak, write or read German, so I cannot modify the text or check the grammar. My qualifications include a Bachelor of Fine Arts degree in photography. To see my work, please view my Freelancer portfolio. (I am also attaching a PowerPoint show as an example of my work.) I look forward to working with you.