Upgrade BIOS version interrupted due to Power trip

Dear all,

I am using Dell servers R620. Yesterday, I upgraded 2 servers to latest version: 2.0.19. When 2 servers were running upgrade process, the power tripped and upgrade process interrupted. Then, I power on but it did not go into Bios screen. It standed in "Configuring Memory .....Done" Screen. I could not do any thing.

Any one could help me to fix this problem?

Thanks so much. !!