Avast – Virus Cleaner and Worm Removal Tool

Avast Virus Cleaner is a FREE virus and worm removal tool that can be installed to and launched directly from a portable USB device. This is a nice tool to have available for those extreme situations when you might encounter an already infected computer. For many common infections a virus or worm can be removed quite easily using this Portable Antivirus tool. Avast has a solid reputation for outstanding antivirus software.

Free Registry Cleaner – Registry Recycler

Registry Recycler is a Portable FreeRegistry Cleaner. It can be used to quickly clean and optimize your Windows Registry in an attempt to help improve your Notebook or PC performance. Registry Recycler supports the cleaning and optimizing of  Microsoft Windows XP, Windows 7, and Windows 8 registries, and also includes defragmentation and automatic registry backup features.

Wise Disk Cleaner v7.96 Portable

"Even though we could have done without the nag screen, this free disk cleaning utility performed very well during our tests. Even beginners will appreciate how easy it is to use."

Designed for Win8, Win 7 (32/64 bits), Vista (32/64 bits), XP, 2008 server, 2003 and 2000.