Hi!
I've moved my blog to the former new blogger beta system a year ago. The migration was successfull and i also used the new beta blogger plattform for 6 months or so, before i moved on to wordpress.
i signed in again at blogger and deleted my beta blogger.com blog. all worked well. after a few days i realized that my first blog at ...blogspot.com was online again. of course i want to delete that blog now, but i'm not able to sign in to the "old blogger.com" system anymore, as i migrated earlier...
hope i'm clear enough... just want to get a blog on the old blogger.com system deleted.
thank you,
rolf

<< I've moved my blog to the former new blogger beta system a year ago. >>

Really? The new Blogger was unveiled in August (http://googlesystem.blogspot.com/2006/08/new-blogger.html).

<< i also used the new beta blogger plattform for 6 months or so >>

Blogger Beta has been available for 4 months.

If you deleted your blog, the subdomain was available for anyone. Most likely, someone else took your blog address.

If you migrate to Google Accounts, your old Blogger account shouldn't be available anymore (or at least it seems logical to be like that).