Because that's what spywares do, ask you to install more crap to get rid of them
Along with Adware you might want to get Spybot Search and Destroy. Pretty much the best combo you can have to scan and delete spywares. Makes sure both of them have updated definitions before scanning. One good way to scan is in Safe Mode since less background processes are loaded. But make sure you do the updating first before switching to Safe Mode.
If you don't know how to get in safe mode, check it
here.