Would this online one help?
http://www.senteacher.org/wk/certificates.php
Basicly you can do it with any drawingprogram, you just need to find some images....i also found a specific Certificate maker program for you
here.
Edit: you're welcome
P.S. You can get equally good/professional results with other programs, all depends on how skilled you are...a program esp. made for it is the easiest (saves time too).
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