The HP T5720 has a standard Phoenix Award BIOS. Press F10 on power up to get into the BIOS screens.
It supports three boot devices and these can be set to:
I'm not sure exactly what range of USB devices are supported under the USB option, but I plugged in a USB pen-drive that had Tinycore 3.6 on it and that booted and ran without any problems.
The operating system is Windows XPe. In my two examples one was running SP2 whilst the other was on SP3.
Any comments? email me. Added June 2011