I can't view my OS commerce site

[greenapple]

I am new to OS commerce and am in the process of developing my first site. Everything has been uploaded ok and I am now using the admin page to refine all of the options, add product etc. However, once I navigate away from the admin page I can't seem to get back. The admin page is currently not secure and I have tried using history in my web browser to get back to it as well as typing in the address but nothing seems to work. When I try to navigate to my site I just get a white page. What have I done???

 

Any help would be appreciated!