when i open google home tab, then all by itself yahoo opens and even though ive tried blocking it through an extension, and as soon as i open my computer, chromium opens even though ive deleted it from my desktop , idk what's going on?

You may have to go into Programs through the Control panel and delete Chromlum from there if the icon is just deleted than chances are that Chromlum is still in your programs and still on your computer also you could of had your Homepage hijack by Malware or Spyware and you could always download a free software to stop or control that on your computer.