Windows Mobile Device hangs on splashscreen

      Windows Mobile Device Center (pre-Windows Vista uses Microsoft ActiveSync) offers device management and data synchronization between a Windows Mobile-based device and a computer.

When you connect your Windows mobile device to the computer, Windows Mobile Device Center (WMDC) detects your phone and a splash screen will be displayed and starts.

But suddenly one day, when plugging the device, the WMDC splash screen comes up but hangs forever at "Please wait while windows mobile device center starts".

Uninstall and reinstall WMDC doesn't help in this case.

Cause:
For communicating with mobile device, WMDC uses several ports:
    * Inbound TCP:
          o 990
          o 999
          o 5678
          o 5721
          o 26675
    * Outbound UDP:
          o 5679
    * Outbound TCP:
          o 990
If one of above ports is used by another application, WMDC won't start and connect to mobile device.
Resolution:
You need to determine which application uses or blocks those ports using Netstat.exe utility.
1. Open Command Prompt (click Start button and input 'cmd' into the search box)
2. Type in "netstat -aon" (without the quotes) and press ENTER.

You will see the list of all connections (incoming and outgoing) running on your computer. For example, in my case, the line TCP 0.0.0.0:990 0.0.0.0:0 LISTENING 4688 in the picture above means that application with PID (process identifier) 4688 is listening on port 990.
3. To figure out the name of this application, you can use Task Manager (by pressing CTR+ALT+DEL or right click on Taskbar).
Click the Processes tab. If you do not have a PID column, click View, click 'Select Columns', and then click to select the PID (Process Identifier) check box.

Click the column header that is labeled "PID" to sort the process by their PIDs. You should be able to easily find the process ID and match it to the program that is listed in Task Manager.
4. When you found it, simply end the process or uninstall the application which is using that port and try to connect your mobile device again.