Recommended freeware/shareware for your PC :
Cleanup Software
CCleaner
It does a very nice job of keeping your PC in tiptop condition. Cleaning of Registry, Clearing of temporary internet files,cookies of various internet browsers etc..
Download Link: Download .
Auslogics Disk Defrag
Does the defragging efficiently and quickly. Comparatively better than Windows Defrag Tool.
Download link: Download
Misc
DelinvFile
Able to delete almost every possible type of invalid files which you have trouble getting rid of. Shareware though. 3x usage before requring to register =( .
Download link: Download
Rainmeter
Rainmeter is a desktop customization platform. Through Rainmeter, you can enhance your Windows computer at home or work with skins: handy, compact applets which float freely on your desktop, much like Windows Sidebar gagdgets, or dashboard widgets for the Mac.
Download link: Download
RocketDock
RocketDock is a smoothly animated, alpha blended application launcher. It provides a nice clean interface to drop shortcuts on for easy access and organization. With each item completely customizable there is no end to what you can add and launch from the dock.Now with added Taskbar support your minimized windows can appear as icons on the dock. This allows for better productivity and accessibility. ( Directly quoted from the website )
Download Link: Download
Wicked Raven 