I have 2 near identical pcs, 1 of which almost instantly flags up a stick on the toolbar. However the other 1 takes some minutes pondering before it does or not at all. So I have to reinsert it in another usb socket. Eventually it is flagged up, weird. You could try inserting the stick then use Start/Control Panel/Add New Hardware to get it recognised (I`m assuming you`re using Windows).
Also, in My Computer, right click on anoptical drive, then Properties. Check that Autoplay is not disabled. If it is, choose View all files (or similar)option. Merry Xmas.