Edison is an excellent power management tool made for Microsoft Windows XP and Windows Vista systems. Edison optimizes Windows Power Management settings for maximum power savings and provides a friendly user interface to configure the power settings.

How to Install Ubuntu in Windows

Wubi is an officially supported Ubuntu installer for Windows users that can bring you to the Linux world with a single click. Wubi allows you to install and uninstall Ubuntu as any other Windows application, in a simple and safe way…

That sums it up pretty well. You can use your Windows (98, 2000, XP, Vista) Control Panel to add/remove it as easily as any other Windows app.

The key thing about Wubi (Windows based Ubuntu Installer) is that you do not have to do any partitioning. It simply creates a file in Windows that both systems treat as if it’s a separate partition. You can choose the size of that file when you install.

Transform Windows XP into Windows 7 without using Customization Pack

Windows 7 provides lots of new features along with a newly designed interface. It looks very similar to Windows Vista but there are many GUI changes like redesigned taskbar, Explorer, new boot screen and login screen, etc.

If you are still using Windows XP but want to enjoy the new Windows 7 look, then this tutorial will definitely help you.

Returnil Virtual System 2010 Home Lux

This is probably one of the best software i have come across in terms of protecting your PC 

Returnil Virtual System (RVS) is a program which aims to provide protection to users in an unorthodox manner. Usually when a user wants protection against malware, and other bad things, he or she installs security software like Avira, Kaspersky, Norton, AVG, NOD32, etc. which actively, and on demand, detect and remove infected files. Although the new 2010 version of RVS also includes an anti-virus/anti-malware component, RVS's core method of system security is this: it creates a "virtual copy" of your main system partition (the partition which you have Windows installed) and whatever changes are made to your computer are dumped when you restart your computer (there are opinions to tweak how it does that, but generally speaking, that is how it works). This approach is the ultimate protection because even if you download malware unknowingly on your computer, RVS gets rid it (100% completely) when you restart your computer. Of course, any other changes made to your computer are also undone (like Windows Updates; so be sure to turn RVS off when running Windows Updates). However, please note, RVS is not a replacement for your main security software. Let me repeat that again, RVS is not a replacement for your main security software . 

SUPERAntiSpyware introduces free “online scanner”

SUPERAntiSpyware - a popular and effective security software which protects users again spyware, malware, adware, trojans, rootkits, homepage hi-jackers, worms, dialers and parasites (has free and commercial versions) - today has released a free "online scanner".

The major advantage of this "online scanner" is it comes in the form of .COM instead of .EXE so if you have any malware on your computer blocking .EXE files, you will still be able to run this "online scanner" without problems.