Usually you have to press a series of keys to boot in to the recovery partition. And it isn't a boot like with windows. You will probably be propted 'are you sure you want to continue with hard drive restore' and that is about it aside from you seeing it reinstalling the operating system.
Repair, reinstallation and using the recovery partition are three separate things:
-Repair is used for windows XP. It repairs just the OS files and leaves your personal files and software intact
-Reinstallation is taking a DVD / CD and installing the OS from scrath. This requires reformatting the hard drive / partition and installing the OS on the formatted drive / partition
-Recovery partition is a separate part of the hard drive (or DVD) that is created by most manufactureres of laptops and desktops (HP, Dell, etc). These are accessed by pressing certain keys at startup (before windows even loads) which will begin the process or recovery. This recovery will restore your drive to how it exactly was 'out of the box'. This includes software and the OS that came with the device. All personal files and programs installed after you bought the computer will be erased.
You have two partitions right now (more than likely). One is the recovery partition that has all of the install files needed for your recovery software to reinstall the OS on your other partition. So one holds the recovery information and the other holds the actual OS and system files / programs / ect.
If you use the software recovery you won't have an option of creating any more partitions. It will just reinstall the OS / software on the other partition - you can't get around that unless you use another DVD to install the OS.
If you use another DVD to install the OS you will have the option of created multiple partitions on the same drive, at that time you can create one drive for the OS and programs, and anotehr one for your music files and what not. Realize in doing this there is no going back because you will more than likely need to erase the recovery partition to accomplish this.
Dual booting with Ubuntu is easy, you literally install Ubuntu on the partition with Vista / XP. Then you use the partition utility that is already present in the software to allocate disk space between Vista / Xp and Ubuntu (essentailly saying hey i want this much space for microsoft and this much for Ubuntu). After that the boot loader program will give you the choice every time you boot up from that point forward of booting into Linux or Windows.