If you have an old BIOS that does not support live USB booting, there is a way to get your PC to boot without native USB booting support.
So you would first need to download plop boot manager
After that extract the file.
Once when you have done open the folder, go to
Windows and then right click on a file called
InstallToBootMenu.bat and then
run as an administrator (it is important that you do so otherwise it will not work)
After you do that, follow the prompts and it should install this to your boot menu.
Now everytime you boot your PC you will see two options whether to boot into Windows or plop, so you should select plop and then you will be given options as to if you want to boot into a cd, USB drive etc.