problem about edit products details(responsive_sheffield_blue)

I started to input the first product details.
It's ok without problem.
but when I tried to click the "edit" button to revise this product again,
the page is empty . what's wrong ?
And when I go the the admin home page again , this product is still there.
And I tried to click the "edit" button again . the page is empty again.

see the attached two photos

First of all, you need to change your admin folder ASAP.
Secondly, you bypassed the question as to your version of Zen Cart
Third, you bypassed the posting tips which again asked for the version and other info.
Since your problem is in the admin, we can't look "under the hood" bur from what I can see in your second image you have a partial page display. Take a look at the page source and try to see where the page load stopped. That can get us closer to a solution.

And, depending on your version, take a look at the logs directory for any debug files.