[ozzy47]

Is this for some sort of demo site?

--------------- Added [DATE]1390787570[/DATE] at [TIME]1390787570[/TIME] ---------------

Well either way do this:

Add a new plugin.

Product: vBulletin
Hook Location: profile_editpassword_start
Title: No Edit Password
Execution Order: 5
Plugin PHP Code:

if ($vbulletin->userinfo['userid'] == 'X')
{
	print_no_permission();
}

Where X is the id of the user.