Default Style Set
 

I had a Default Style set, let's just call it Bob. Okay, so I wanted to replace Bob with George (another style that I wanted to be the default instead). When I uploaded George in place of Bob, I got an error saying there was already a style named George. So then it overwrit Bob and now there's no Default at ALL. So now the default is the default vB style.

Sorry if this confused you, I was trying to make it simpler. -.- Any ideas?

ok
goto your styles selection thingo.. click Modify for the style Default
change the Template Set and Replacment Set to the style you want.. hit OK, there you go :)