Hello there : )
Please first download and install Malware Bytes - Update it and do a full system scan. If/when it finds malware have it fix all results.
www.malwarebytes.comI recommend Avira Antivirus the basic version is free and from my experience is the most light weight and the most effective. It is widely used in the corporate realm as well. After Malware bytes download and install Avira from free-av.com.
Then download and install HiJackThis and do a system scan and copy your log into this thread and I/we will dissect it. There are also Hijack this forums where they analyze your results as well.