That is entirely dependent on the server you published it to. This really
isn't a PowerPoint question as PowerPoint doesn't play any role in
publishing your file to the Web. PowerPoint just prepares it to be
published.

If you can't figure anything else out, try creating a blank presentation
with the same name as the original. Then, publish that to the Web in the
same way you published the original. Now, the original should be gone and
all you'll have left is a blank presentation on the Web.

--David