If your APC will Boot, we suggest the follow checks to restore your board. 1. Make sure power is connected. 2. If your system will not boot, re-install with the latest firmware which is available in the library. (Step by step instructions are included with the download.) 3. If your APC will still not boot after re-installing with the latest firmware, your bootloader in the SPI ROM may be corrupted meaning you need to re-flash it with the SPI Rescue ROM. In order to do this you will need an SPI programmer and another computer. The SPI Rescue ROM's for all APC products are located in the library along with a detailed tutorial explaining how to go about it.