Files/Anti-Virus
Avast! Virus Cleaner – Scans the computer for a specific set of viruses and worms.
Malware Bytes Anti-Malware - Anti-Malware software.
Spybot S&d Portable – Scans the computer for a specific set of viruses and worms.
Gparted - - Bootable partition editor.
UNetbootin - create a bootable USB.
Recuva - Recover deleted files.
7-Zip Portable – An open source file archiver that supports 7z, ZIP, GZIP, BZIP2, TAR, RAR as well as others.
CCleaner Portable – An optimization utility that cleans the registry and removes unwanted files from the computer.
PC Decrapifier – Uninstalls trialware and annoyances from new computers. Makes cleaning up a new computer much easier and saves a lot of time.
Visual C Runtime Installer All-In-One - Install all Visual C runtime libraries with one installer.
Documents
OpenOffice.org – OpenOffice.org which includes a word processor, spreadsheet, presentation tool, drawing package and database. Can also open most Microsoft Office documents.
Foxit Reader – A portable PDF reader.
Networking/Web
Angry IP Scanner – Scans a range of IP addresses so you can see which ones are in use. Also tells you hostname, MAC address, open ports, computer name, workgroup, and logged in Windows users.
CurrPorts – Allows you to see detailed information about all of the TCP/IP and UDP ports being used on the computer including which program is using them. Also allows you to close out the port and kill the process that opened it.
Chrome portable – Portable version of google chrome.