My steps (after backing up everything before deleting it):
1. Uninstalled VS2012 Pro from Windows 8 64 bit
2. Removed the following registry entries:
HKEY_USERS.DEFAULTSoftwareMicrosoftVisualStudio11.0; HKEY_USERS.DEFAULTSoftwareMicrosoftVisualStudio11.0_Config; HKEY_LOCAL_MACHINESOFTWAREMicrosoftVisualStudio11.0; HKEY_LOCAL_MACHINESOFTWAREMicrosoftVisualStudio11.0_Config; HKEY_CURRENT_USERSoftwareMicrosoftVisualStudio11.0; HKEY_CURRENT_USERSoftwareMicrosoftVisualStudio11.0_Config;
Note that I did not delete or clean up HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftVisualStudio11.0 which contained the license key
3. Deleted the following directories:
C:ProgramDataMicrosoftVisualStudio11.0;
C:Program Files (x86)Microsoft Visual Studio 11.0;
C:UsersUserNameDocumentsVisual Studio 2012; C:UsersUserNameAppDataLocalMicrosoftVisualStudio11.0; C:UsersUserNameAppDataRoamingMicrosoftVisualStudio11.0
4. Renamed a .Addin file in C:UsersUserNameAppDataRoamingMicrosoftMSEnvSharedAddins to stop it loading.
5. Installed VS2012 Update 1 from an ISO (ex MSDN download), carefully choosing not to try to import settings from VS2010. Did not install patch_KB2781514.
6. Installed VS2012.2 from an ISO