I thought I had a virus

One of my long-time computer clients called me about something unusual on their computer one afternoon.  A message appeared full-screen on their Windows computer stating a serious malfunction had occurred on their computer and to call them.  My client thought their computer was infected with a virus and they couldn’t close the message and doing anything else. When I arrived on site, I couldn’t find any trace of malware and their McAfee LiveSafe security program said it was secure.  I asked more questions about what they were doing before the message popped up. What really happened was my client accidentally landed on a malicious web page when they were seeking a legitimate one they saw on TV.  My scans did find some unwanted programs which are exactly viruses. My client’s computer is better now and they will be cautious where they web browse from now on- I hope!