You can download many different utilities, some for free and others for a fee, that will help solve problems on your PC. Some of these are more helpful than others. You should decide for yourself about the value of individual software packages, but I recommend the following packages.
Sisoftware Sandra Utilities
Sisoftware Sandra is an excellent information and diagnostic utility. This package’s extremely detailed reports about every aspect of your PC, including hardware, drivers, and installed software, can help enormously when diagnosing computer-related problems.
Create Report on the Tools tab in Sandra utilities is a useful tool that generates a complete report about your computer. This tool does everything the Windows 7 System Information panel and System Health Report do, but it provides even more detail about your PC.
Windows Sysinternals is a suite of tools and applications from Microsoft that help you manage, troubleshoot, and diagnose your Windows systems and applications. These extensive tools provide huge amounts of detail about your PC when troubleshooting problems. However, some of these tools are quite complex and are designed for experienced computer users.
Zinstall zPOD is an excellent software package that enables you to turn your copy of Windows and all of your software into a virtual machine that can be stored on a removable hard disk or even a USB pen drive. You can then use this virtual machine on any PC. This means you can always have your copy of Windows and your programs (perhaps even your files) with you whenever you need them.
GoToAssist is software that performs the same functions as Windows Remote Desktop and Windows Remote Assistance but offers a few additional functions for serious technical support. Most notably, it allows you to restart the remote computer (which can be essential when performing some support functions), and it runs on and from Apple Mac computers.
Another software package held in extremely high regard by many computer professionals is SpinRite from computer security specialist Steve Gibson. This utility runs from a disk or USB flash drive and checks your hard disk for errors, physical or otherwise, that are causing malfunctions and/or data loss, then helps repair problems. It is an extremely useful piece of software.
Windows Memory Diagnostic
The Windows 7 installation DVD contains a memory diagnostic tool, but Microsoft also provides this other memory diagnostic tool if your Windows 7 install DVD is lost or damaged and you can’t boot into the computer repair console in Windows 7.
Norton Ghost from Symantec is one of two packages on this list that create system images of Windows. Although this functionality is already built into Windows 7, these packages offer additional backup and restore functionality for people who work in a corporate environment.
Acronis True Image
Acronis True Image is another system image backup and restore application. This package is useful in business scenarios where you need more control over Windows 7 system images than is available through the Microsoft Windows Image Backup that ships as part of Windows 7.
Paragon Partition Manager
Sometimes you need a utility to manage the partitions on your hard disks. Windows 7 includes a partitioning tool, but it’s not especially powerful. Paragon Partition Manager can make working with partitions much simpler.
Acronis Disk Director Suite
Acronis Disk Director is another partitioning management package that will make working with and managing partitions on your hard disks much simpler.
Source of Information : Microsoft Press - Troubleshooting Windows 7 Inside Out