1) Download and Install Free Version of AVG-http://www.free.avg.com
2) Download Trial Version of Malwarebytes Anti-Malware and Install.https://www.malwarebytes.org/
I recommend buying Malwarebytes Antimalware full version.
3) Some PUPs and harmful data could still bug you even though antivirus and antimalware softwares show positive results in full system scan. Download this .exe file and scan your system (no installation required)http://www.techsupportall.com/adware-removal-tool/
I use the same tool that saved my computer where traditional antivirus betrayed me.