Data taken from Windows Vista ...
  
C:\Program Files\Yahoo!\
  
C:\Documents and Settings\All Users\
Application Data\Yahoo! Companion
  
C:\Documents and Settings\User\
Application Data\Yahoo!
  
Yahoo App CLSIDs ;
  
{FFFFE1D1-E40D-49a1-9622-BC59BD1879C3}
{EB2BA65E-41F6-4F64-92A6-216CDFFDF577}
{1CAE874F-F5C7-4BCC-BA46-9AD26DF35B93}
{07CDAAD9-1226-4C6D-B774-C00E7B323484}
{41D7CEE0-D91F-498C-BC88-4A6BEE46C2BC}
{7D831388-D405-4272-9511-A07440AD2927}
{9EDCCD11-960D-49AE-B523-C6B5AB7E1345}
{39DCCEAF-C749-4390-9953-527CF916935C}
  
HKEY_CLASSES_ROOT\CLSID\{02478D38-C3F9-4efb-9B51-7695ECA05670}
  
HKEY_CLASSES_ROOT\CLSID\{1147DC83-6208-4dca-8E88-DD45BAAB3043}
  
HKEY_CLASSES_ROOT\CLSID\{11CB4723-D5A1-4a55-8D1D-5C2679D54CF5}
  
HKEY_CLASSES_ROOT\CLSID\{1E57256D-9F39-4267-AB39-D7813D644C5A}
  
HKEY_CLASSES_ROOT\CLSID\{31371420-098D-4C0E-A11E-EBEC2305DD01}
  
HKEY_CLASSES_ROOT\CLSID\{37B8167C-B9A4-4316-94B2-67B64BB2BA7C}
  
HKEY_CLASSES_ROOT\CLSID\{3A06AA27-D94B-48C2-BB55-9FD0FF2120E3}
  
HKEY_CLASSES_ROOT\CLSID\{46140CE4-76FE-440E-AE88-4C2272BC05C7}
  
HKEY_CLASSES_ROOT\CLSID\{6E40017D-FB6A-4804-BDE4-3BB09F1719C1}
  
HKEY_CLASSES_ROOT\CLSID\{81017EA9-9AA8-4A6A-9734-7AF40E7D593F}
  
HKEY_CLASSES_ROOT\CLSID\{9F9C4C5C-2BA8-4E00-A697-9F710BB1026B}
  
HKEY_CLASSES_ROOT\CLSID\{B7A0E898-93E5-43f4-B99A-6C70B303699C}
  
HKEY_CLASSES_ROOT\CLSID\{C60CCE95-6AF9-4E74-B66B-3212D19F1D2F}
  
HKEY_CLASSES_ROOT\CLSID\{D40A62D1-8FC0-4F03-90C4-0DE03BE73A41}
  
HKEY_CLASSES_ROOT\CLSID\{DDCED22E-D018-471D-9A5C-A4EA2F21133D}
  
HKEY_CLASSES_ROOT\CLSID\{E1A2D448-6334-45ec-8800-6D7F71DC87FC}
  
HKEY_CLASSES_ROOT\CLSID\{EF99BD32-C1FB-11D2-892F-0090271D4F88}
  
HKEY_CLASSES_ROOT\CLSID\{F51C15D4-3D0A-4DBA-A095-EBCC09F24DA2}
  
HKEY_CLASSES_ROOT\CLSID\{F9A10D86-182A-4946-869B-70C3D109D14D}
  
HKEY_CLASSES_ROOT\CLSID\{FBE30D66-39A2-4b72-8B43-6D4C335A6F34}
  
HKEY_CLASSES_ROOT\CLSID\{FDAD4DA1-61A2-4FD8-9C17-86F7AC245081}
  
HKEY_CLASSES_ROOT\CLSID\{FDAD4DA1-61A2-4FD8-9C17-86F7AC245081}
  
HKEY_CLASSES_ROOT\TypeLib\{003028C2-EA1C-4676-A316-B5CB50917002}
  
HKEY_CLASSES_ROOT\TypeLib\{0548C79F-7B8C-455D-B228-97D35371BB62}
  
HKEY_CLASSES_ROOT\TypeLib\{4A1E52AC-64F2-49E9-BFD7-0806D9494DBB}
  
HKEY_CLASSES_ROOT\TypeLib\{61A2027D-B837-4080-A925-6E30E10DEF32}
  
HKEY_CLASSES_ROOT\TypeLib\{78DB07DF-483E-4829-AB44-ED7952083584}
  
HKEY_CLASSES_ROOT\TypeLib\{8A1AB044-787D-4309-8410-709768E484AB}
  
HKEY_CLASSES_ROOT\TypeLib\{A2C55651-A23E-43CA-B63D-C10B99EFF7E0}
  
HKEY_CLASSES_ROOT\TypeLib\{A31F34A1-EBD2-45A2-BF6D-231C1B987CC8}
  
HKEY_CLASSES_ROOT\TypeLib\{AD34BE7D-2603-43DD-8D1F-E4431D42C44E}
  
HKEY_CLASSES_ROOT\TypeLib\{B722ED8B-0B38-408E-BB89-260C73BCF3D4}
  
HKEY_CLASSES_ROOT\TypeLib\{B82D18E0-1649-48DE-92D7-AA89BBB5F0AD}
  
HKEY_CLASSES_ROOT\TypeLib\{D2EA97F6-6235-4B2D-B5AA-A4472B9CE557}
  
HKEY_CLASSES_ROOT\Yahoo.AntiSpyPlugin
HKEY_CLASSES_ROOT\Yahoo.MessengerCompanionControl
HKEY_CLASSES_ROOT\Yahoo.PopupBlockerPlugin
HKEY_CLASSES_ROOT\YBrowserToolbar.YBrowserToolbar
HKEY_CLASSES_ROOT\YCAPlugin.CAYASPlugin
HKEY_CLASSES_ROOT\YMERemote.YMECompPlugin
HKEY_CLASSES_ROOT\YPUBC.BlockerCtrl
HKEY_CLASSES_ROOT\YPUBC.DataStore
HKEY_CLASSES_ROOT\YPUBC.PUBHTMLEventHandler
HKEY_CLASSES_ROOT\YPUBC.StringList
HKEY_CLASSES_ROOT\yt.CacheLoader
HKEY_CLASSES_ROOT\yt.Clickstream
HKEY_CLASSES_ROOT\yt.YTHelper
HKEY_CLASSES_ROOT\yt.YToolbarBand
HKEY_CLASSES_ROOT\YTabBar.YTabBarControl
HKEY_CLASSES_ROOT\ytbbroker.YTBCustomizerAssistant
HKEY_CLASSES_ROOT\ytbbroker.YTBMessengerAssistant
  
HKEY_CURRENT_USER\Software\Microsoft\Office\
12.0\Outlook\AutoDiscover ;
  
HKEY_CURRENT_USER\Software\Yahoo
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\
{B82D18E0-1649-48DE-92D7-AA89BBB5F0AD}
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\
{D2EA97F6-6235-4B2D-B5AA-A4472B9CE557}
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Yahoo.AntiSpyPlugin
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Yahoo.MessengerCompanionControl
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Yahoo.PopupBlockerPlugin
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YBrowserToolbar.YBrowserToolbar
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
yt.CacheLoader
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
yt.Clickstream
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
yt.YToolbarBand
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YTabBar.YTabBarControl
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
ytbbroker.YTBCustomizerAssistant
  
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
ytbbroker.YTBMessengerAssistant
  
YahooMusicEngine.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_DISABLE_UNICODE_HANDLE_CLOSING_CALLBACK
  
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Management\
ARPCache\Yahoo! Companion
  
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Yahoo! Companion
  
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Yahoo! Toolbar
  
HKEY_LOCAL_MACHINE\SOFTWARE\TrendMicro\
NSC\TmProxy\ProtocolHandler\ymsg
  
HKEY_LOCAL_MACHINE\SOFTWARE\Yahoo
  
HKEY_USERS\S-1-5-21-██████████-██████████-
██████████-1144\Software\Yahoo