This is actually not yahoo tools for Anti Boot protection, but after I run this Yahoo Ace, I recognize that Yahoo Ace can be used as Anti Boot for Yahoo Messenger Version 9. The author of Yahoo Ace calls this software as Yahoo Advance Client Extension.
Why I call this software as Anti Boot? Because Yahoo Ace can modify the service of Yahoo Messenger such as: File share, cam invite, pm, conference invite, peer to peer and many more. Yahoo Ace can blocks or allows that service as you wish. That service can be on or off just like Anti Boot. Its can be used for all user (non buddy list) or limited user (buddy list) for Block Protection. That why I call this Yahoo Ace as Anti Boot.
Download Yahoo Ace Anti Boot
It also can be used as mic Locker and many of yahoo tweaking service. I hope you enjoy this Special Anti Boot.