HP pavillion a1610n Disaster

My hp got railed by rootkits and various other viruses and was trashed to the point where my BIOS was gone. I replaced the harddrive but then learned it trashed my onboard video as well. after borrowing my friends videocard i still get the same "Check signal cable" msg. I tried different moniters and even swapped out the processer but nothing. Any suggestions? thanks

 

I cant even get into the BIOS i cant get any kind of picture other than a "Check signal cable" msg. But I noticed using onboard video and the card that the moniter displays the msg when the harddrive is unplugged and goes into powersave when the harddrive is inserted