How do people manage to download garbage like this onto their computer
Most adware will come bundled with installation programs for things such as tools and games that may be otherwise trusted. They're also obtained via drive-by-downloads.
download
this and run it, (please run this first, it's important!)
Then, do a full scan with Malwarebytes,
then download
this and do a scan with it,
and then run
this and run it. If doing these things doesn't fix the problem and the adware persists, contact an IT specialist and tell them what you've done so far (from what I can understand, you've already run Mbam once, and, if you've followed the steps I've told you above, you've also used Rkill, Adwcleaner, and JRT). They may have advanced knowledge that most of us will not be able to offer.