Process Explorer

Software - System Tools

Sysinternal's Process Explorer is an advanced process management utility. It will show you detailed information about a process including its icon, command-line, full image path, memory statistics, user account, security attributes, and more.
 The top always shows a list of the currently active processes, including the names of their owning accounts, If you point your mouse poiner over the process names you will see tooltip popup giving you the path of the file on the hard disk as well as full name of the process.

Process explorer also tries to verify each process against its publisher. You will see Process, Description, Company name and Verified Signer columns. This making process explorer an invaluable tool in finding out malicious/ harmful process and removing them.

You can download Process Explorer from this link

CCleaner

Software - System Optimizer

CCleaner is perhaps the most popular freeware temp files and registry cleaner. We need to use this type of software because almost all the infection that occur through internet, enter through the temp files, and unfortunately windows does not remove temp files automatically.

In order to prevent infection through temp files is to set ccleaner so that it runs automatically with windows startup. You can do this setting in CCleaner's window by clicking as below.
(options > settings> Run Ccleaner when computer starts)
-add recycle bin
Cleaner > Advanced > check the box "Custom files and folders"
Options > Include > Add Folder
browse and select C:\RECYCLER or C:\RECYCLED in XP or C:\$Recycle Bin (in Vista)

(adding the recycle bin to the ccleaner helps a great deal, that will automatically remove the files from the recycle bin, it is necesary for your protection, because the latest security threats add virus files inside the recycle bin which are executed when the computer restarts. )

Run the Cleaner and the registry menus in CCleaner. The automatic running uses only the Cleaner menu. You need to run the Registry menu manually, to remove the obsolete registry entries, particularly if you are trying to remove a virus or an unwanted application from your computer.

 You can download CCleaner from several download sites including FileHippo.com