I do not notice a malware called Great Find in the system until the computer begins to slow down. Internet Explorer, Chrome and Safari get rather small ads on the right top corner. Key words are underlined at times. My friend helped me with steps in Chrome Help Forum and this article. But Safari is still performaning weirdly. kaspersky scans a file and delete it already. Any good idea? Thanks in advance!
Window 8.1 64bit
Intel Celeron processor
4GB RAM

Two things I can think of are:
Get MalwareBytes (make sure it is their site) which has a free malware scan tool that works great.

http://www.malwarebytes.org

Second bring Windows up in safe mode and run the virus scans from there. I find that normally will catch the last of the hooks that the malware or virus installed.