I also have a Samsung laptop (QX412), and I'm trying to get into boot menu. F12 does nothing.
F8 displays:
Edit Boot Options for Windows 7
Partition: 2
Hard Disk: 74aba7c9
[ /NOEXECUTE=OPTIN
Enter=Submit, Esc=Cancel
????
I can select the primary boot drive in the bios, but last time I did that (on another laptop) it messed up my HDD. So would rather just select a temp boot device than change the default.
Also, not sure which is the right usb to select...