http://www.nikonchat.com/nikon-coolpix-disk/

What can I do to get my pictures to transfer to computer?
I cannot get me pictures to transfer from my Nikon Coolpix 4600 camera to my computer. It was working fine until I followed some tip on how to get my computer to start up faster. Now it won’t work. My USB ports are okay. When I plugged my camera into my USB port I use to get a screen that read “removable disk (E)” and then it would let me pick how I wanted to transfer my picutres now I don’t get that screen at all. Can you help me. Thanks
Goto Start->Run and type in SERVICES.MSC then press OK.
Scroll down to “Shell Hardware Detection”, right click it and select “Properties”. Change the startup type to “Automatic”.
Finally, click “Start” on that same screen to start the service.
This service detects when a device is plugged into the computer such as a USB hard drive or thumb drive and brings up the window you describe. It also will autostart any CD-ROM or DVD put into the system if it supports autoplay.
Hope this helps.
Edit: You may also need to do this for the “Windows Image Aquisition Service”
Cory Hall Machine Room: Then (1997) and Now (2010)