I had never heard of Webroot and did a quick review of the product and it would seem their are far better A-V programs available. I had used Norton and wasn't very happy with it (a resource hog) and am now using Kaspersky. It is a top notch program and I haven't had any issues with it. It does a pre-scan before installing which is a plus. If you can't swing the expense of changing programs, there are a number of sites that will do remote scans of your system One of the best that I found was Housecall by TrendMicro. Check it at
housecall.trendmicro.com. Good luck. One other thing you can try is a free (at least used to be) trial of Blacklight, which is a root kit detector. You'll have to Google that one.