A friend of mine had recently her green card stolen. Some weeks later she started to apply for a replacment card by filling out a PDF form on her computer with Windows 8.1. She then decided otherwise and stopped filling out the form. Not even 15 minutes later she got a phone call from a woman who pretended to be from the USCIS (the US immigration agency), asking her why she stopped filling out the form and offering her to help her to get a replacement green card. My friend was confused, kind of believing that the woman was indeed from USCIS, but luckily did not give her any information in that phone call. Since then my friend got apparently some emails, allegedly from this woman, and now another phone call in which this woman again tried to get some information out of my friend.
It seems to me that my friend has some malware on her computer that keeps track of what she is doing or typing and then sends this information somewhere - and that without the installed (and paid for) Norton security software giving any alarm.
What can I do to help my friend to find out what is going on on her computer, and how can she get rid of a possibly installed malware?
Thanks for your help!