Hello SylviaMy name is ***** ***** I'll be happy to assist you.You say the company is named Nan Info Sec? This is not a familiar name.Could you please tell me what the messages are saying?Thanks!
That is a scam. They are not associated with Microsoft. Please do not call them or allow them control of your computer or they will compromise it.
What is the number they give you to call?
To ensure that there is not viruses or malware on your computer already, please go to ESET's site and use their free, online scanner. It is located here: http://www.eset.com/us/online-scanner/
ESET is a reputable anti-virus company and their online scanner is the best, ***** ***** I've used in years. Just follow the link and click "Scan Now". It will want to install an applet and update the definitions then it will run.I advise using this scanner once or twice a month to keep your computer free of malware.
What issue are you having with your computer?
You are welcome. If I have been helpful, please kindly rate my service. Otherwise, if you are having further issues with your computer I would be happy to assist and we can roll it under the $39. Depending on the magnitude of the issue(s).