Do you mean that when you open Windows Explorer it is no longer there under "my computer"?
Or the transfer wizard does not start up?
Sometimes, this is very easy to fix: Just open Windows Explorer and navigate to where you can see the drive letter or name of whatever device causes the problem--- CD burner, camera, USB drive, whatever. Right click on the device and select Properties. Select the "AutoPlay" tab, select "Prompt Me Each Time To Choose An Option." That's it!
Well, that's *often* it. But sometimes, especially if some other software has inserted itself into the mix, it takes a bit more to restore control of the autoplay device to Windows. This site lists many possible solutions: click here