ITunes has stopped working - iTunes 12.1

Question

I just updated iTunes 12 to 12.1 on two Windows 7 x64 systems. On both systems, iTunes fails to run now although 12.0 ran perfectly.
Upon clicking on the iTunes program icon, I get a dialog:
          Runtime Error!
          Program:  C:\Program Files\iTunes\iTunes.exe
          This application has requested the Runtime to terminate it in an unusual way.
          Please contact the application's support team for more information.
This is followed by a second Windows crash dialog on my first system:
          iTunes has stopped working
          Problem Signature:
                Problem Event Name:                APPCRASH
               Application Name:                       iTunes.exe
               Application Version:                    12.1.0.71
               Application Timestamp:              54c76235
               Fault Module Name:                    KERNELBASE.dll
               Fault Module Version:                 6.1.7601.18409
               Fault Module Timestamp:            5315a05a
               Exception Code:                          c000041d  
               Exception Offset:                         000000000000940d
               OS Version:                                 6.1.7601.2.1.0.256.48
               Locale ID:                                   1033
               Additional Information 1:             b956
               Additional Information 2:             b956b0c787c12b5653b9ee496e31c42e
               Additional Information 3:             2fe2
               Additional Information 4:             2fe2087e98073ca074b5d037e75ccb2c
On my second system, there is a slightly different failure:
          iTunes has stopped working
          Problem Signature:
                Problem Event Name:                APPCRASH
               Application Name:                       iTunes.exe
               Application Version:                    12.1.0.71
               Application Timestamp:              54c76235
               Fault Module Name:                   btmmhook.dll
               Fault Module Version:                6.3.0.6300
               Fault Module Timestamp:          4c5239cd
               Exception Code:                         40000015
               Exception Offset:                        000000000001a3ee
               OS Version:                                6.1.7601.2.1.0.256.48
               Locale ID:                                   1033
               Additional Information 1:             87cb
               Additional Information 2:             87cb48742dd7844ff1df33721f990ecd
               Additional Information 3:             9d5c
               Additional Information 4:             9d5c064844e6d8e27291889a991b03f2
None of these failures ever occurred previously with my configurations (including 12.0) with iTunes. And no, the video compatibility version (64-bit installer with 32-bit payload) doesn't fix these problems either. And I cannot find any copy of the 12.0 version to revert to!!!
Clearly this update wasn't sufficiently tested before being released. Help!!!!
          - Dov

Answer 1

For general advice see Troubleshooting issues with iTunes for Windows updates.
The steps in the second box are a guide to removing everything related to iTunes and then rebuilding it which is often a good starting point unless the symptoms indicate a more specific approach. Review the other boxes and the list of support documents further down the page in case one of them applies.
The further information area has direct links to the current and recent builds in case you have problems downloading, need to revert to an older version or want to try the iTunes for Windows (64-bit - for older video cards) release as a workaround for installation or performance issues, or compatibility with QuickTime or third party software.
Your library should be unaffected by these steps but there also links to backup and recovery advice should it be needed.
tt2