Screen not working just a black screen

[joematt]

hi i took my friends pc to fix for him I put windows 8 on it and that was all fine but I went into the bios to see what was happing in there and I changed something and now all I get is a black screen can anyone help me as soon as possible please because he wants me to pay for it unless I fix it

sorry for got to mention its a ARC21 packard bell

 

[zink1701]

Does the PC have on board video and a discreet Graphics card? If you have both then you could of disabled the card in bios. Plug the monitor into the on board graphics and see if you get a picture. If only on board graphics or no joy with that then try resetting the bios by using the jumper pins on the motherboard. They located usually near the CMOS battery (looks like a watch battery) it will be markes as CLR CMOS or something similar. Short the pins with the jumper then boot the pc and see if you get a picture, Turn off the pc and remove jumpers back to original position. This will reset the bios back to defaults