Customers of Spectrum Cable can get free security software that they call Security Suite. Part of that software package is a program called Anti-Bot Scanner. However, you do not have to install the Security Suite software to use it. Just go to this page:
Scroll down toward the bottom until you come across the Anti-Bot scanner, click it to download the installer and then run the program. It only takes a couple of minutes and it scans the hard drive and memory. I am a Spectrum customer, but it doesn't appear that you have to be a customer to use it.