Monitoring the mainboardNext on the list, we're going to install some motherboard temperature monitoring software, much like Motherboard Monitor 5 on Windows. Of the applications I've tried, KSensors has just the right level of features and functions, though others exist. Installing KSensors will install the common components used by all monitors (i.e. the lm-sensors server), as well as for all KDE-based applications, so let's apt-get install ksensors. Still as root, run sensors-detect to scan your PC for temperature sensor chips. Just hit enter at each prompt, the defaults know what they're doing.
You're gonna have to edit a couple of configuration files at this point, to get all the sensors drivers to load on boot. The sensors-detect program tells you what needs to go where, and these will vary from motherboard to motherboard - type "nano /etc/modules" in another root terminal to open the /etc/modules file in the nano text editor, highlight what needs to go into it with the mouse, then middle click into the text editor to paste the selected text. Do this for /etc/modutils/local, and run update-modules as root. Now you can either try to load the drivers into memory one by one, or reboot. To be honest, rebooting is probably easier. Once the system is back into Gnome, you'll find KSensors under the Debian Menu, Apps, System: