lostpassword page – autogenerate vs link

Hi all

I might be missing something but I want to force my blog to send a new password link instead of an autogenerated password. On this link wp-login.php?action=lostpassword. But one of my blogs uses sends password link to change password on the wp-login page my other blog sends a password. They are both latest installs of wordpress, so I am coming to the conclusion you can set this somewhere to force it to do either way. Or one of my plugins is interfering with the process. Any help would be greatly appreciated.

Thanks

Chinty