Your program removes error files from
C:\Users\User\AppData\Local\Microsoft\Windows\WER\ReportArchive
but it does not remove traces of the same files from the registry sections listed here:
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Windows Error Reporting\Debug]
"StoreLocation"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\Debug]
"StoreLocation"