matador_r 0 Newbie Poster

fearlier today i removed the battery from my computers motherboard to reset the bios password, as i was unable to change the boot order to reinstall the OS from disk. i was told this would simply reset all the info such as the password and time/date.
once this was done i powered up my computer but there was no video output.
whilst removing the battery i did unplug some cables but i am sure they all went back in the right place as i took a picture to refer to when re connecting them.
the computer is definately on, and the keyboard lights up for a second, but there is no video output at all.
i have no idea what could have caused it, and wondered if anyone could give me some advice as to what direction to turn.
the graphics card is built into the motherboard, so if it is a problem with that would i need to replace it completely?