... Can anyone help me find a place to down load for free OS X 10.5 Leopard?
No version of OS X is free. You may be able to purchase Mac OS X 10.5 "Leopard" from aftermarket vendors such as Amazon. The price is high. It is not available to download from any legitimate source.
You clearly have some software that is conflicting with Snow Leopard since it runs perfectly OK on your model MacBook Pro.
Be certain that you installed Snow Leopard using this disk:
Grey discs are system-specific and will not work with anything other than the exact model Mac with which they were included.