Online Subnet Calculator:

Online Subnet Calculator 

Active Directory Troubleshooting:

Part of the Microsoft Windows Server 2003 Resource kit.

ActiveDirectoryTest 

PC Diagnostics:

AIDA - credit to Tamos Miklos, CTO Lavalys Consulting Group Software

PCDiags 

CD/DVD Test:

Nero CD SpeedTest,

Credit to Erik Deppeero

Nero CD/DVD Test 

Folder Size:

Credit to Brio out of Canada? Apparently an excellent coder and modest. A true paradox.

Folder Size

TCP Port Scanner

PortScanner 

 Windows Zip

Credit to Johan Savås

ZipCentral v4 

VNC

Credit to all of the members, past and present, Computer Laboratory at Cambridge University, UK

Well done. Cheers

VNC v4.0 

NS Lookup:

A throw back to the old winsock days. Credit to "someone" in the UK

 NSLookup