The reset vector is at f000:ffff I think and it is inside the BIOS ROM itself.
Start up procedure is:
1. POST tests, at start of each test a number ("Checkpoint") is written to port 80 so a failure can be traced from the last number sent out.
2. Set up a default interrupt vector table, it might be modified later by other ROMs claiming them.
3. Initialize other ROMs, including the one on the video card, this is typically where you see the video manufacturers logo on the screen.
4. Attempt to load the boot sector to a fixed memory address. If successful, the loaded code is then executed and should in turn load the main operating system.
You can learn a lot by opening a terminal window and running the Debug program. When you have the prompt on the screen, type debug then '?' to get help.
Brian.