I hate the new adware creations some of these folks have come up with. They're basically viruses designed to show advertisements. Some redirect your browser and other tcp/ip traffic through one of their dedicated servers to track your internet activity. Others just plant pop-ups and search engines on your machine.
We've come a long way in the last 25 years or so - What used to be just pranks became hacks then viruses and then adware and spyware. The latest trends are putting digital systems in things you would have normally considered "inert" - Items like clothing and tires and toaster ovens. Soon "big brother" (government) and his "uncles" (large companies) will be watching everything we do, making "suggestions" to improve our lives along the way.
Anyway, back to the problem at hand. Get an adware detection/removal program and check for viruses, adware and spyware. After running it twice, monitor your system to see if the problem has gone away. Some of those programs do a pretty good job and can remove all but the most offensive problems.
If you have one that is very stubborn, you may need to get into the registry and do some manual removal. If you find a virus/adware/spyware program that is particularly stubborn, it will usually show up in scans even after you've removed it. Recurring runs will always show it as being active. If that's the case, do a search on the internet and you'll probably find a few websites with instructions how to manually remove the virus.
To recap: Download or buy a virus/adware/spyware removal program and run it first, and if you can't get rid of one or two stubborn ones, use the virus program to identify them and look them up on the internet to find specific removal instructions. Then run the virus/adware/spyware detection program again to make sure your system is clean.