Explorer.exe using 100%

in the description for what the hotfix is for is your pc doing the same?
You have some corrupted .wav files in a folder on a computer that is running Windows 7 or Windows Server 2008 R2. When you open the folder, you encounter the following problems:
The computer responds slowly.
You cannot perform any other operations.
You experience high CPU usage in the Explorer.exe process.
Note To temporarily resolve these problems, restart the Explorer.exe process. For more information about how to restart the Explorer.exe process, see the "More Information" section.

You may also encounter problems when you use other applications or operations to open the corrupted .wav files. For example, if you try to use Windows Media Player to open the corrupted .wav files, Windows Media Player stops responding. Additionally, the Wmplayer.exe process generates high CPU usage.

it may not be required to use this hotfix on your system

i suggest you run kaspersky free virus remover tool >> Virus Removal Tools i have used this with great success as well as clients and friends please follow the instructions.
http://support.kaspersky.com/viruses...ol2011?level=2

Kaspersky Virus Removal Tool 2011 is a free software intended to disinfect infected computers, removing viruses, Trojans, and spyware, as well as any other types of malware. Kaspersky Virus Removal Tool 2011 uses the same highly efficient algorithms for detecting malware as Kaspersky Anti-Virus. Algorithms include a full-functional anti-virus scanner, technologies developed for detecting vulnerabilities in installed applications and operating systems, and a technology for running scripts intended for removing complex and compound viruses. The utility can be used as a free anti-virus software.

Kaspersky Virus Removal Tool 2011 is not intended for real-time protection of computer. After the disinfection of the computer is complete, the application should be uninstalled from the hard drive and replaced with the real-time protection anti-virus:

Kaspersky Virus Removal Tool 2011 provides no update function. The up-to-date version of the application with the latest version of anti-virus databases is always available on the website of Kaspersky Lab Technical Support service.

Advantages:

The application is absolutely free.
Simple application interface.
Installation on an infected computer. Including:
in Safe Mode of Microsoft Windows;
when a real-time protection of anti-virus is running.
The installation process does not require interaction with the user anymore.
Closing the main window is enough to uninstall the application form a computer.
Automatic scan and disinfection:
search of malware using signature databases;
heuristic analyzer;
search and neutralization of rootkits;
search of applications with known vulnerabilities;
non-signature search of malware based on "cloud" technologies (when Internet access is available).
Manual scan and disinfection:
collection of information about an infected computer and system;
interactive creation of disinfection scripts.
What's new in Kaspersky Virus Removal Tool 2011:

The user interface has been improved.
The application installation and uninstallation have been simplified.
A full-functional use of the application from a flash card has been implemented.
The process self-defense has been implemented.
The advanced disinfection has been improved.
Compatibility with real-time protection anti-virus applications has been improved.
Active use of the "cloud" technology of Kaspersky Security Network.

run the kaspersky antivirus tool and see what it finds