welcome to the forum.
i suggest you download install and scan with malwarebytes antimalware as a first opion.
http://filehippo.com/download_malwarebytes_anti_malware/ don’t forget to update.
then i suggest you do a scan with hijack this and post the result here.
http://filehippo.com/download_hijackthis/
good luck and let us know one the progress.