What happened to my Windows Experience Index? Windows Aero?

I am using a laptop with Windows 7. MY index was around 4.6-5. I don't remember which. Then suddenly one day. It went to 1! It says that my graphics is Desktop performance by Windows Aero. AND now a few things have changed. Like my internet and taskbar, I could see my wallpaper like through frosted glass, and when I moved my mouse onto something in my taskbar, a little window where I could preview it would be there, and yet now it isn't. Has anyone else had this problem?