I would like to delete this post,because the problem has been solved after I reset the virtual memory.
Recently I reinstalled the OS Windows 7 Ultimate 64bit since then Logitech Webcam Software is loading very slow. Before I reinstalled the OS W7 it was very fast. I have another Vista OS it also loads very fast.
I use the latest driver and software for the logitech and others.
The motherboard is Asus Rampage III Extreme and 4GB of Corsair DDR3 RAM, the graphic card is 2 Ati Raedion 5770 (use Crossfire), HDD 750GB and the CPU is Intel I7 950.