It might be that BlitzBasic is still installed. To change the file associations, in the Windows Explorer, go to Tools->Folder Options and choose the "file types" tab.
Or shift+right-click a .bb file, choose "open with", then choose "select program", select b+ and check the box that says "allways open this type of file with this program".
support.microsoft.com/kb/307859
Or shift+right-click a .bb file, choose "open with", then choose "select program", select b+ and check the box that says "allways open this type of file with this program".
support.microsoft.com/kb/307859