If the restart issue is caused by CB (after being uninstalled) it means that one of it's components remained installed.
Please check to see if there are any files left in
\Program Files\COMODO\Comodo Backup
Or any of the following sys files:
Some of them remain installed on the system, if you also have COMODO Cloud installed, because they are common components used by both COMODO Backup and COMODO Cloud.
You can also try the CB 4.1 BETA
and try to disable the "Scan files for backup purposes" option in settings.