Post corrupt in admin account

There is one post on my site that I created in my admin account that I cannot edit. When I open to edit, it hangs up and ghosts itself, repeating screen text over and over. I thought it was a problem with a plugin the post uses, until I asked my web consultant if he has the same problem when he logs in with his account, but he does not. I logged in with his account, and sure enough, the post is editable.

Do I need to create another admin account? Do I delete the old admin account? Is this straightforward or are there any pitfalls?
I can’t find any answers with searching forums and appreciate your help.