Procrastination ahead! When starting QGIS, does the popping up of the cmd prompt window annoy you as much as it annoys me? If you want to solve this, put the following vbs script in your PATH/bin folder (or anywhere else, if you wish).
Check the path to qgis.bat in the script and change it if yours is different. Then, go to the QGIS-Desktop shortcut and in the options dialogue point to the vbs script as target. Your done - no more popping cmd windows when starting QGIS!
Set WshShell = CreateObject("WScript.Shell") WshShell.Run chr(34) & "C:\OSGeo4W\bin\qgis.bat" & Chr(34), 0 Set WshShell = Nothing