This can happen if there is a compatibility conflict with other running applications in Windows. To correct the issue, you will need to change some autorun settings.
– Download the autoruns program from Microsoft Sysinternals
– Install the application.
– Double click autoruns.exe and click YES or OK.
– In the “Applnit” tab, look for any entries and uncheck them.
– After making changes, close this window and try relaunching Sibelius.