Are both systems in uefi mode asked post #7.

i did in UEFI and Legacy both fail to boot

You make the flash drive to match the machine usually. What are the machines running in? Secure boot? Uefi? (I forgot what that windows deal is... quickboot??)

normally uefi fast boot but have modified to legacy because the usb is formatted in fat 32

You should be able to boot in uefi mode with usb formatted as fat32. The efi partition on an internal drive is formatted fat32.

Virtual drive is a sort of file and within it is a replica of a physical drive that you can format and such. It is possible to do many tasks with that file much like you'd do with any hard drive.

It is quite easy usually to install a virtual machine program to run a number of OS's at the same time the host is running. As in two OS's at the same time.

just downloaded VM software for my Windows OS but i couldn't find anything to run off my xubuntu OS

Your comment above from post #3 is confusing. If you have a 'live' bootable usb, you don't "boot up in windows" or "boot up on Linux" as has been pointed out above. If you have a properly created usb drive, it should boot on any computer that is capable of booting a usb. Often the option to boot the usb is under the HD option in the BIOS firmware. If you have a properly created bootable usb, it does not matter if there is a windows OS installed on the computer or if there is a Linux OS installed on the computer or if there is no OS installed on the computer. If the computer on which you are failing to boot the Xubuntu live usb is only 3 years old, there is no reason it should not boot so probably something else is going on here.

" i couldn't find anything to run off my xubuntu OS"

Normally you install an OS to a VM. It is possible but not directly supported that one can boot from a usb. Many web pages on how to.