I have three pretty well identical Dell OptiPlex 755s and on two of them have updated the bios to A22 with no issues, The other still has A17 and I have downloaded the latest bios file and tried to update the PC using the self loading file but every time I run it I get a message saying the update has failed and "could not find firmware in memory". What can I do now? Will using a usb stick make any difference, I don't want to try it unless its safe. I think the old bios may be the cause of some other networking issues I am having with this particular machine.