If you don't get an answer here you might try:
www.desktoppublishingforum.com
where there are a lot of font and Adobe experts, and maybe a few VISTA
ones coming along <g>
I've just checked my Fonts folder and I do have Arial Black showing
there -- the file is arbl____.ttf (note to long underline ____ which is
4 characters to make the 8+3 file name -- arial black goes back to 1995
<g>
I wouldn't like to say that arial black came with VISTA or with
something I've installed some of which do go back in time -- like Lotus
Smartsuite <g>