Your PC would of course also have to be capable of booting from an SD card.
or if the PC has a SD port (but cannot boot directly to it because the BIOS dont support a SD boot like my samsung NC10 Plus), try following if the PC can boot from the USB:
- boot from a USB-adapter with the SD card in it
- start PLOP bootloader in a multiboot menu which is on the SD card
- remove the USB adapter
- put the SD card into the SD port
- choose the USB boot menu in PLOP which is still on the screen
- and see if your SD card is recognized; in this case, choose the TinyCore menu
This is usefull for me for avoiding a USB port blocked by a stick; then a mouse can later be connected to it.