I have almost no problems with anything on my computers. We have 6 running, 2 spares, and 2 laptops. We have all been running the Microsoft Security Essentials for years. Unless we fail to notice that a 'pop up' stating that we have an 'infection' is not from Microsoft Security Essentials, and click on it, we haven't had any problems. Each of us, all 6 of us at one time or another during the last few years, have clicked on a pop up that told us that Microsoft had detected a virus and if we clicked the X it would get rid of it. Instead, it accepts/allows an infection! We learned quickly that if this pop up happens, just turn the computer off immediately, complete shut down. Then start it on again and run a scan to be sure that there was no infection. If we do this, we find that everything is ok. We have had calls from 'scammers' telling us that they were 'Microsoft' and they could clear a virus that they had detected on our computer. I was the first to receive such a call. The 'lady' was nice. She said that she was with Microsoft and that they had, through the main server, detected a virus on my computer. She wanted to have access to my computer so she could 'clear out' the virus. I was stupid enough to let her have that access. After about 3 minutes she said that it was cleared and that I was now in control of my computer again. I thanked her. She then said that I owed her $99.99 for the service that she had rendered. I asked her why Microsoft would try to charge me that amount of money to do something that took only about 5 minutes to accomplish. She said that it was a 'standard fee'. I again asked her if she worked for Microsoft and she said that she 'did work for Microsoft'. I said, "Are you employed by Microsoft?" Again, she said that she did work for Microsoft. I told her that she was not employed by Microsoft and she admitted that she only 'did' work for Microsoft. I told her to get off my 'F**king' phone and hung up. Since then we have had two or three other calls similar to that one. My son-in-law got one that told him for $549 he could get rid of the virus. I 'played' around with the last one for about 40 minutes asking questions and making statements of how I could get rid of the virus myself. He always had a 'come back' about how I could not get rid of it, that it would always come back unless he was allowed to make changes to my computer for $450.
Oh, and when I was scammed into letting that woman into my computer, I immediately shut it down, wiped it, and reloaded my OS on it.
Again, the Microsoft Security Essentials is free, and most of the people that I know use it. I have used Norton, McAfee, and several others that didn't do half (IMHO) that the Microsoft SE does. NO!! I am not affiliated with the Microsoft people!!!