GRUB Selections

How do I change the default GRUB (and maybe LILO, too) boot selection on a multiple-OS system?

The GRUB config in /boot/grub/menu.lst (GRUB1) or /etc/default/grub (GRUB2) should contain a DEFAULT line that specifies which of the given operating systemd should be booted by default. For GRUB 2, you need to install the new configuration by doing:

sudo update-grub

after modifications in /etc/default/grub or /etc/grub.d/*.

Installing a Driver

How do you install drivers for hardware after installation (e.g., a card you've added later or that wasn't configured during installation)?

In Linux, the hardware driver is a kernel module that must match exactly the kernel version installed (i.e., if you update the kernel, you have to update the kernel modules as well, and if you install a new hardware module, it must be compiled from source to match the running kernels version). Loading or unloading modules works with

modprobe name_of_module

and

rmmod name_of_module

which should be done automatically by the udev daemon if it detects new hardware and there is a module present for the hardware's vendor and product ID (and, if the module is not blacklisted in /etc/modprobe.d/*.conf).