μTorrent (also called microTorrent or uTorrent, short for "µT" or "uT") is a freeware BitTorrent download client, written in C++. It is the most widely used BitTorrent client now, outside China (where XunLei is more popular and has the has the largest number of users in the world).
Tiny Core Linux (short for TCL) is a lightweight to the minimal, tiny Linux operating system with a GUI. It's constructed based on the 3.x version of Linux kernel with BusyBox, Tiny X, FLTK and other small software, which can be booted from the CD-ROM, USB flash drive or HDD. Additionally, due to all its components running in the RAM, its running speed is super fast.
SideSlide provides a highly customizable launch-pad (or called start panel) which can be hidden (will display when using the mouse to activate) on the edge of desktop screen for programs, documents or folders.
Windows built-in Explorer, because of combination with browser and some fancy functions, sometimes its open-speed may be very slow, at this time you can try Mini Explorer (ME2 for short), this fast and lightweight Windows Explorer alternative.