The adsense above and below my posts will not center for some reason.
http://www.ordinarystars.net

I've tried putting the <center>...</center> tags when I inserted it, because it works on my other blogs. But ever since I got a new template, it doesn't work.

I went into the HTML edit and found the widget and couldn't find any of the widgets.

Any help?

Try wrapping this around your AdSense code

<div style="text-align: center">your AdSense code</div>

Better would be to set up a class in a css file and apply the class to the div, but this should work.