This morning I was on Yahoo homepage and was about to type in a URL address and all of a sudden I was redirected to a screen with warnings about my computer being infected with spyware. It asked me to call 877-913-7847 It threatened that my credit card and password information was at risk. I could not do anything on my computer, not even force quit. I finally pressed the button and turned off the laptop. After I turn it back on everything seems normal. It is scary that whatever this spam screen is could control my computer and I could not do anything. Is my computer infected in any way? Please help. Thanks.