newbie needs help urgent please

[desire]

hi when you create account on my website and log in all is ok till you try to buy somthing you can click on a item and it goes into the shopping cart ok but when you go to check out the pages are missing bits the first page is fine but get to second page where you have to choose payment the buttons are missing but if you refresh the page they show up ok any ideas please help i tried everything this has only seemed to have started since i accidently deleted checkout_php. file but i have reinstalled it

if you wanna try this out on my site its www.desiresandfun.com

i have set up a dummy account you can use log in name [email protected] password admin