One of the tools that comes with Windows operating systems is the Malicious Software Removal Tool. It updates with the monthly MS updates and it runs a quick scan once a month. However, it may be a good idea to actually add another layer of security and run a full scan from time to time.
So how do you run this tool? First, press the Windows logo key+R. This will bring up the following window.
You just type 'mrt' in the input box and hit the OK button. This will bring up the dialog box for the MRT.
Now you just click on the Next> button and you will be presented with the following dialog box.
You then select the Full Scan radio button and click on the Next> button to start the scan off. It may take some time to actually complete, but this will give you another layer of security for your home PC.
Now this will only find known software that Microsoft has added to the MRT so it isn't a silver bullet. Stay safe out there