How do you know if your PC is being attacked & hacked by unscrupulous fellows if you're connected in the Internet? I noticed that sometimes when I'm surfing, there's a sudden black screen in my monitor and goes off for awhile. After a few seconds it goes back to normal operation. Is this one of the symptoms if you're being invaded? I tried using Zone Alarm but my PC slows down. I got an old Pentium 1 processor and my OS is Windows 98. Anybody can give me an advice?