Some time ago, I was really stupid, and somehow managed to install the program spi, or similar, as far as I remember. Since then, on every reboot, banners like "99bitcoins" and "Tom's Hardware" keep popping up. If I delete them in the messages settings, they reappear after a reboot. I am quite sure that spi has been removed for good from my computer, but I still can't find the reason for this to keep happening. I have also tried to use tools such as bitdefender to get rid of everything. That is despite I really don't like to use antivirus programs on my Mac. What should I do to get rid of this?