The program you want is Unetbootin.

You will probably need to go into the BIOS setup of the laptop to change the
first boot device to "USB hard drive." Different BIOSes use a different
keystroke to get there; Del is popular.

A 1 GB drive is big enough. I actually found that an 8 GB drive was awkward; I
wound up formatting it to NTFS. You want to make sure the USB drive is marked
"bootable" in Gparted.