If you get this, DON’T CLICK.
This seemingly helpful warning is designed to scare you into clicking the link, and thus downloading viruses into your computer. Don’t do it. The real tip off is that I am not using ANY version of Microsoft Windows — I use Linux. It is a Skype message intended to trick you into downloading malware by claiming that it has found malware and your computer needs immediate (read that — “without thinking’) attention.