DiagAxon is a free program that allows you to check the current availability of a host on the network by performing a ping operation. Additionally, the application enables you to analyze the way in the global network packets (traceroute) as well as scan ports. The results can be copied to clipboard from the 'History' window and pasted in a document, for further processing.
Complete Internet Repair does exactly what it says. It attempts to repair everything internet-related, including networking problems. Video tutorial and a portable version are also available.
With inSSIDer, you can inspect your Wi-Fi and surrounding networks, scan and filter hundreds of nearby access points, troubleshot the competing access points and clogged Wi-Fi channels, and more.
Simple Port Tester is a free program by PcWinTech.com to help users test if their ports are open with just a few clicks. Now supports 52 Languages. Portable version also available.