You can stop this CLICK HERE
The above is a hoax. It is a scam. It is a cheap trick designed to alarm you. It takes advantage of the fact that Explorer is Explorer is Explorer. Windows Explorer and Internet Explorer are essentially the same thing, when it comes to viewing files that are on your harddrive. Just because you see files in a web browsing window, that doesn't mean that the whole world can see what's on your computer. The window up above has a tag with the line
iframe src="file:///C|/"in it. This line means "show what's on the hard drive of this computer to the browser window" and that's it. It's the same as opening up Windows Explorer. Nothing more. Anyone who looks at that page is going to see what's on the hard drive of their computer, not yours. It's essentially a mirror, held up in front of your face to show you yourself.
If you have it, try opening up this page in Netscape. See what you get.