Hard drive spin should be controlled by either apm or acpi. It works on my machine, and I use apm (apmd) to control it. For instance, "apm --suspend" will put my computer into "sleep" mode.
Screen blanking is automatic on the console (text-mode only). It is controlled by xscreensaver, which can be configured through its own configuration program, for X11R6.
A "service" is called a "daemon" in UNIX-land and in Slackware Linux as well. There are several "application" that can run as daemons, such as sendmail, apache, etc.
To run application (NOT a daemon!) even after the console has been closed, try entering "name_of_application &" on the command line.
Finding processes and changing their state is done through "ps" or "top" (to display processes) and by "kill" to stop them. Try entering "man ps", "man top" and "man kill" on the command line for more information.
Try running "lilo" to setup a different configuration for your computer. Usually, it does not matter which drive Linux is installed on, as long as lilo can "reach" it...
You seem to know very little about Linux... Am I wrong? If that's the case, please read the "Slackware Essentials" book. It's an excellent introduction to Linux in general and to Slackware in particular.
You can find it on the Slackware site, at the following address:
(Or, even better, order it from the Slackware store!)