PowerPoint templates get corrupted over time. It usually starts with a template that was designed by a print graphics designer as an after thought after designing the logo and the business cards: creating slide layouts without paying much attention to the technical issues of programming a template that can be (ab)used by thousands of employees. Then over, slowly but gradually, "foreign" templates infect the original until nothing is left of the original.
I go back to zero every time I design a new presentation. The file that I put up in the SlideMagic template store is pretty much the one I start every new presentation design project with. It is really simple. You can customise it with your own colours and you are good to go.
When creating a new slide, go to the "Layout" button in the top left of the menu to create a select a new slide layout.