right, I can make a bootable USB from an iso file, but for work I need to burn four bootable iso files (all for windows 7) onto one USB to reimage my laptop. I have no idea whether its possible to concatenate them and use rufus or if there is a better tool. and before its suggested I don't have a disk drive to use.
YUMI should be able to do what you need: http://www.pendrivelinux.com/yumi-multiboot-usb-creator/
YUMI runs on Windows, and you can use it to install multiple ISOs to a USB alongside one another (USB space permitting). YUMI uses a small menu when the USB is booted to let you select the ISO/OS to boot from the USB drive.
Choose your USB drive in step 1, choose the "Windows Vista/7/8 Installer" option for Step 2 (it's near the bottom of the drop-down menu), and point it to the Windows 7 ISO file in Step 3. YUMI should take care of the rest.