Red Button is a free program for Windows optimization.

Red Button Features:

Reduce the space occupied by system on a disk
Switch off and remove unnecessary, disturbing to work components
Increase speed of loading, work, turn off of system
Clean “junk” files
Raise safety and convenience of system
Reduce degree of influence on environment
Lower system charges

The program …

Sysinternals Suite 

The Sysinternals Troubleshooting Utilities have been rolled up into a single Suite of tools. This file contains the individual troubleshooting tools and help files. It does not contain non-troubleshooting tools like the BSOD Screen Saver or NotMyFault.
The Suite is a bundling of the following selected Sysinternals Utilities:

AccessChk
AdExplorer
Autoruns
BgInfo
DebugView
Diskmon
DiskView
Filemon
ListDlls
LogonSessions
ProcessExplorer
ProcessMonitor
ProcFeatures
PsExec
PsPasswd
PsShutdown
RegDelNull
RegMon
RootkitRevealer
SDelete
ShareEnum
Sync
TcpView
VolumeId
WhoIs
WinObj
ZoomIt
Much more…

:: Download …

If you are not familiar with the Alt-Tab task switcher in Windows, it’s a keyboard short-cut (hot-key) to enable fast switching between applications/windows. This feature has been in Windows since Windows 3.0 and is largely unchanged since Windows ‘95! Alt-Tab Thingy is a replacement to add brand new features to …

Ultimate Windows Tweaker has over 130 tweaks. These have been categorized under seven heads and can be accessed through a common interface, just like your Windows Vista Control Panel.
Ultimate Windows Tweaker

Personalization – These tweaks help you personalize your Windows Vista, just the way you want it to appear. Tweaks for …

Have you ever wanted to remove Windows components like Media Player, Internet Explorer, Outlook Express, MSN Explorer, Messenger…  How about not even to install them with Windows ?
nLite – Build your own custom Windows disk

nLite is a tool for pre-installation Windows configuration and component removal at your choice. Optional bootable …

Desktop Central – Freeware Windows Tool

Desktop Central provides a set of free Windows tools that Windows Administrators might require on a day-to-day basis. It has a set of nine tools, viz: Wake on LAN, GPO Update, Shutdown/Restart Tool, Software Inventory Tool, Join/Unjoin Computer Tool, Remote Task Manager Tool, Currently Logged …

Freeware utilities for Windows, free to use for both private and commercial users.
InfoDesk – Desktop Tools for Windows

Just small utility for Windows to display everything you want. All modules/tools can be invoked by system-wide hot keys. Fully customizable interface is also available.
InfoDesk Features:

Coder Tools 
Notes
Console
CPU Monitor
Net Meter
System Information
Notepad
Clipboard History 
Windows Explorer 
Calculator
Calendar 

:: Download InforDesk
:: MiTeC
:: …

Scan your Windows system with freeware tools  “RunScanner”.   This freeware also can scan and detect changes and misconfigurations in your system too. 
RunScanner

RunScanner is a freeware windows system utility which scans your system for all running programs, autostart locations, drivers, services and hijack points.
You can use Runscanner to detect changes and misconfigurations in …