There are so many tools using which you can create bootable USB flash disks. For example, you can use the UNetbootin to create bootable Live USB disk drives for Ubuntu and other Linux distributions. Similarly you can use Rufus to create bootable Windows installation media including both the USB flash disks as well as the a bootable CD or DVD. I personally keep a pendrive with Puppy Linux on it so that I can use it to boot into my PC in case Windows fails to boot.
Whether you use these tools or any others to create the bootable USB drive, all of them ask you to reboot your PC to check the freshly created bootable media. And if there is a problem with the bootable disk drive, then you will have to reboot back in Windows to attempt creating the bootable USB drive once again. If you do not want to keep rebooting your PC just to see if the bootable USB drive is working or not, then you can use the free Bootable USB Test for checking whether the disk drive is working properly or not.
Bootable USB Test is a portable tool and can test the USB disk drives, hard disk drives, ISO disk images and IMA disk images. Typically, you would just select the USB disk drive from the drop-down list in the Bootable USB Test window and click on the Start button. This will start the loading of selected USB disk drive and testing it via QEMU virtual environment.
In the QEMU virtual environment, you can actually see the bootable disk drive loading and you can interact with the loading as usual. This way you can easily verify whether a bootable disk drive is working as intended or not. If it fails to boot or you see some error during the loading in QEMU then probably it has a problem and you will have recreate the bootable disk drive using some other tool.
Conclusion: Bootable USB Test can test a bootable USB drive, hard disk drive and ISO/IMA disk images and show you using a virtual environment whether it works or not. It is very convenient and can save you from rebooting your PC multiple times.
You can download Bootable USB Test from http://wintoflash.com/download/en/.