Few things... first change your password in Yahoo. They were recently hacked. You can also do what Damit says and use Outlook.com or live.com or hotmail.com email. Same place. Download the CCleaner, Malwarebyte and SuperAntiVirus.
Run CCleaner first as talked about above. https://www.piriform.com/ccleaner/download
https://www.malwarebytes.com/mwb-download/
I would recommend registering this one for future but you dont have to just don't activate the trial. http://www.superantispyware.com/ Don't start the trial just use the free.
Scan with both Malwaybytes and Super to see if you see a problem. If just tracking cookies dont worry. If other let us know. Screen shot or log will work. To stop the tracking cookies and advertising do this in Chrome.
In Chrome install the following. AD Block.. blocks ad's. https://chrome.google.com/webstore/detail/adblock-plus/cfhdojbkjhnklbpkdaibdccddilifddb?hl=en-US Ghostery... blocks trackers
https://chrome.google.com/webstore/detail/ghostery/mlomiejdfkolichcflejclcbmpeaniij?hl=en To control Flash install this. Flash Control. https://chrome.google.com/webstore/detail/flashcontrol/mfidmkgnfgnkihnjeklbekckimkipmoe?hl=en and if you can make a screen shot of your programs installed. Control Panel - Programs and Features. List is by install date and list the newest things installed for the past year or so. Look for things like Coupons stuff like that.