Have a look in the bios of the laptop see if you have the option to boot from Usb device.
To get to the bios turn the laptop on, look at the first screen and it will tell you what key to press to enter bios setup.
Once in there go to the boot section menu of the bios screen see if boot from usb device is in the list.
Make sure it is set as no 1 in the boot device list, save the setting in the bios and exit.