Free tool for file conversion between PDF, Tex, Word and so on

pandoc (Download from http://johnmacfarlane.net/pandoc/index.html)

A set of tools useful for network analysis on Windows OS

Traceroute: trace network to network hopping to the destination host
(Enter tracert command on Windows console)

wget: fetch contents from network
(Download from http://gnuwin32.sourceforge.net/packages/wget.htm)

cUrl: fetch contents from network
(Download from http://curl.haxx.se/dlwiz/?type=bin&os=Win32&flav=-&ver=2000%2FXP)

Wireshark: trace the protocol layering, packet, data frames when contents are transmitted from the local machine to hosts on the network
(Download from http://www.wireshark.org/download.html)