How to fix the Checkout in your store…
If you are having troubbles with the checkout in your store, the best way to solve it is renameing the checkout files of your theme, so Magento can take those files from his base.
Go to: \app\design\frontend\default\YOURTHEME\template and rename the checkout folder: (example: “checkout” change it to “__checkout”) ,also go to: \app\design\frontend\default\YOURTHEME\layout and rename the checkout.xml to __checkout.xml
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