This was definitely one of the most common questions I got from customers when I had to clean their computer of viruses, malware, spyware and adware. My was, first of all no antivirus program is 100% at removing everything. It just does not happen, because this is not a perfect world.
My advise to the customer was always make sure your antivirus software is updated and not expired. I can't you the number of times I had to tell someone your antivirus software expired quite awhile ago and had not updated or was even working. Their response was always the same, what do you mean it was not working. It never told me it was going to expire.
They always asked me what antivirus software I preferred. Well I had used Mcafee quite a few years ago and later on it was not as good. Today's versions seem to be doing much better. Kaspersky is not bad, but can be very picky and may want to remove something that is not a problem. There are others like Windows Defender, which is very simple and the least intrusive antivirus software. Other favorites are Webroot, Nortons and Eset NOD32.
One thing you should watch out for are computer service centers offering managed antivirus's to the home user. If you are a business, the managed antivirus is not a bad idea. It basically means that the service center is monitoring your computers for indicators of an infection. I have found and seen with my own eyes, that some places do not even check on these systems until the customer calls about an issue. If you are going with this make them put it in writing and have them show you their system.
The place where I worked had one person that was supposed to be monitoring this, really never did. Yes they were basically lying to the customer. They had numerous home users that bought the managed antivirus, payed a lot of money and still had to bring it in for repair. One person could not manage to monitor hundreds of computers all the time. So my advise to the home user, is to purchase good antivirus software, learn how to scan and clean with it.
Also learn about other programs that can be run to scan and clean various types of infections. My advise is use Free Malwarebytes, Rouguekiller, adaware cleaner and super anti-spyware (I usually stop this from automatically running at start up). Believe me, you could save your self a lot of money. Saving anywhere from $100 to $300 or more for a virus cleaning. The computer service center may add additional items, like upgrading your windows updates or drivers to the system, to jack up the price. These are all things you can do yourself.