Disable the Unread Mail Message on the Welcome Screen
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\UnreadMail\]
"MessageExpiryDays"=dword:00000000
Disable Compress Old Files (This is useful when Disk Cleanup Tool Stops Responding While Compressing Old Files)
[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VolumeCaches\Compress old files]
Windows Explorer Crashes When Opening Folder Containing avi/video files
[-HKEY_CLASSES_ROOT\CLSID\{87D62D94-71B3-4b9a-9489-5FE6850DC73E}]
[-HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler]
[-HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{87D62D94-71B3-4b9a-9489-5FE6850DC73E}\InProcServer32]
Disabling the File Association Web Service (when you click on unknon file it displays 'Windows can not open this file, ... Use the web service to find the appropriate program / Select from the Program list') (XP/Vista/7)
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system]
"NoInternetOpenWith"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer]
"NoInternetOpenWith"=dword:00000001