BootSafe is a tiny application that allows you to restart your PC in Safe Mode with a single click. Without it, starting in Safe Mode usually requires a manual restart and hitting the F8 key.
There are four restart options in BootSafe's single interface. There's a normal restart, which is just that and then three varied safe modes. Minimal restarts with no network or internet access, Networking allows internet access, and Active Directory Services Repair.
While BootSafe works, it's hard to see why it's necessary. If Windows hangs, you won't be able to run the app to restart, so it's hardly a useful emergency tool. It's also not Vista or Windows 7 compatible, which really needs to be rectified.
BootSafe is a quick and easy way to restart your PC in a number of modes, but is hardly the most essential app around.