I often find Malwarebytes Anti-malware software on machines that I work on. Typically these were installed by a knowledgable friend or other “computer guy.” This is truly a fabulous program and I love to see it. I install it on all my personal machines as well, since I find that it is a great safety check for any machine.
Recently I have used the “premium” version of this program, a version that they sell by subscription but which is also sold (for a limited time, I assume, $38.99 as of Feb, 2015) on amazon.com as a lifetime license – a non-expiring license to the full version. Unlike the free version, the premium version runs all the time and runs IN ADDITION to whatever security software you may have. In many cases, it can be run alongside the built in security that comes with Windows 8 and 10. By doing this, you have 2 levels of security, both watching for different things. Currently this is the simplest adequate solution for most everyone.
So my advice is to:
Download and install the free version of malwarebytes. Run a scan and see if it finds anything.
Download at http://www.malwarebytes.org/mwb-download/
Go to amazon.com and purchase the code for lifetime premium service (available as of Feb. 2015 but not for long!)
In Malwarebytes, click on “Go Premium” and then select “I already have a license”
Insert the codes sent to you by Amazon after completing your purchase of the lifetime premium service.