A few readers have written that they recently received Skype phone calls urging them to download and install a system update for Microsoft Windows. Users who visit the recommended site are bombarded with the same old scareware prompts that try to frighten them into purchasing worthless security software. One curious aspect of this scam is that there doesn’t appear to be any actual hijacking malware or downloader involved. If you click the Erase all Threats button in the pop-up generated by the site, youre taken to a page that offers you professional online repair service, and they offer both Mac and Windows plans!”]
Source: https://krebsonsecurity.com/2011/03/rogue-antivirus-via-skype-phone-call/