Farbar Service Scanner, or FSS, is a lightweight, portable tool for diagnosing network connectivity issues directly related to missing or corrupted Windows services.
After running a scan with the FSS tool, it will provide you with an easy-to-read report with the findings. This report will then help you identify the source of any connectivity problems. This can be essential, for instance, when you have successfully removed malware from the OS but you still are unable to connect to the Internet.
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.