Cool Beans System Info is a small but powerful program that monitors your computer's CPU, physical memory, and swap memory usage. The main window displays these three properties in small graphs, each which can be turned on or off. The window is also resizable, taking as little desktop space as you desire. For users with Windows 2000 or Windows XP, Cool Beans System Info also supports the alpha blending transparent look.
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.
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.