Thanks for the help.
Yes it is. On XP, I right-clicked on the USB drive letter > Format > Quick Format before using an application to build a bootable Linux keydrive.
At boot time, I tried USB FDD, ZIP, CDROM successively, to no avail.
Is this really the latest BIOS for that desktop?
System BIOS version 6.00 PG
SMBIOS version 2.4
System BIOS ID R02-A3 12/28/2006