Did you tried to check if control panel is set to be displayed in your start menu? check it by doing a right click on your start button and the click properties, the taskbar and start menu properties should open, under the start menu tab you can either select start menu or classis start menu, select start menu then click customize, this should give you another window, that window is the customize start menu window, on this window go to advanced and under advanced look for control panel and select the option "Dispaly as a link" or "Display as a Menu". If this doesn't resolve the issue then the problem is on the windows registry.