ok, thanks, I've been reading up on boot loaders, so the boot loader is stored on ...
Yeah, basically. In the PC's bootstrapping process, the bootstrap program has to have a consistent place to go so that it will be able to move into memory and execute code that will find the OS. Look around the Operating System Resource Center
for some good info on the bootstrap process as a whole. It may take a couple "bites" to get the idea, but it's really a fairly straightforward process.
Enjoy your Linux experience