If you have access to the EPiServer database directly you can run this script in order to force delete a page. At least if you're using EPiServer 6.
--- Force EPiServer page deletion
declare @pageIDtoDelete int
set @pageIDtoDelete = <INSERT PAGE ID HERE>
delete from tblWorkProperty where fkWorkPageID in (select pkID from tblWorkPage where fkPageID = @pageIDtoDelete)
delete from tblWorkPage where fkPageID = @pageIDtoDelete
delete from tblProperty where fkPageId = @pageIDtoDelete
delete from tblAccess where fkPageID = @pageIDtoDelete
delete from tblPageLanguage where fkPageID = @pageIDtoDelete
delete from tblPage where pkID = @pageIDtoDelete