Same problem. Using Windows 10 on a 64-bit PC, AcroTray has stopped working. No 2015 Reg key to delete. Logs as follows:
Faulting application name: AcroTray.exe, version: 15.16.20045.57024, time stamp: 0x57487806
Faulting module name: combase.dll, version: 10.0.10586.103, time stamp: 0x56a84cbb
Exception code: 0xc0000005
Fault offset: 0x00085d3c
Faulting process id: 0x3d54
Faulting application start time: 0x01d1d14a582a27b3
Faulting application path: C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\AcroTray.exe
Faulting module path: C:\Windows\SYSTEM32\combase.dll
Report Id: 11d5f516-891a-4d0b-aab6-bd2ac1e90350
Faulting package full name:
Faulting package-relative application ID: