As already mentioned, it is critical that the SD card you use is formatted to the correct standard. My experience has been that cards bought e.g. for use with a camera are already formatted correctly. It needs to be large enough to hold the recovery files, but no larger than 4gb. An 8gb card won't work! Using your pc, copy the recovery file or files obtained from Elonex to the root directory of the card. No other files should be stored there. Insert the card into the minibook making quite sure it's the correct way round, which for mine was upside down, with contacts upppermost!!! Switch on the machine and immediately hold down F3 and keep it down. After a short while the recovery screen should appear. Only then release F3 and continue by following the prompts. Select the option to format the flash memory, when it appears. The recovery will take a few minutes and the machine should reboot to the desktop.
If no recovery screen appears after a minute of holding F3 then the machine may be bricked and should be returned to the seller for refund.
It is just possible that the kernal is corrupt... it may be worth trying to restore this first.