CrystalDiskInfo is an Open Source utility that monitors and displays the health of your hard drive, including basic information, S.M.A.R.T. values, and disk temperature. Also available as a portable version.

HWMonitor is a free hardware monitoring program that reads PC systems' primary health sensors: voltages, temperatures, and fan speeds.

PRTG - Free Network Monitor is a network monitoring solution that ensures the availability of network components while also measuring traffic and usage.

CrystalDiskInfo Portable is an Open Source utility that monitors and displays the health of your hard drive, including basic information, S.M.A.R.T. values, and disk temperature. Also available as an installer.

Wireless Network Watcher is a small freeware monitoring tool that quickly scans your wireless network and then lists all the computers and devices that are currently connected.