Bill Quick puts in a kind word for Malwarebytes, which I used to clean up my ex’s computer back in December:
[O]ver the past several years it has been my most dependable tool in combating stubborn malware infections.
I highly recommend it. The only thing I recommend more is hunting down virus writers, skinning them, dousing them in boiling acid, hanging them from lamp posts, and lighting a slow fire under them after stuffing their gullets with their own genitalia.
Which process I also approve; however, you can’t buy that from Amazon, whereas you can buy Malwarebytes there.