EDIT: Well that was working now COMODO BackUp doesn't want to open.
It doesn't open at all?
Please check Task Manager for CBU.exe or GUI_[...].exe and terminate these processes if present.
Try again to open and if it doesn't open create a dump file (Task Manager -> Processes -> right click -> choose "Create Dump File"). Compress and upload the dump file to ccloud.com (you can create a free account) then share it and post the download link.