BIOS update interrupt on Dell

Hi there,
I have a Dell Inspiron 660 and it had BIOS version 2.5 and it was taking longer to boot so I thought I should update the BIOS version, I was doing okay until a power cutout occurred, when power resumed, I tried to boot the computer but nothing happened, the lights on LED is on but nothing else happens, how can I get my computer on again please!
