If I were you, I wouldn't necessarily believe that "notice". Copy and paste a portion the the exact notice you got into Google and run a search on it. You may find others talking about it and being advised that it is a fake notice.
If you don't find others talking about it, then it may be worth worrying about.
You are right Matchett.
There is what is circulating as a fake-virus. Makes it look like you have been messesd up. Of course the object is to click on the “ repair all” link.
I am on a yahoo tech support group and read about it fortunately before it hit me last week. I ran my Avast and Malwarbytes ( which I love!) and found no viruses as I figured.
Polly