I have an hp g56-122us laptop. The problems started a month ago after I took apart my laptop to see if I could put a new sound card in there. I handled the parts pretty roughly, especially the motherboard. After that, every time I turned on my laptop, the power was on, but the screen was completely black. I always had to wait 10 minutes to force the laptop off, then turn it on again. Then, it would boot normally, but the screen flickered and sometimes, the laptop would shut down when I did CPU intensive tasks. I did a chkdsk /r and a Windows Memory Diagnostic, but both showed that my hardware had no problems. I saw a BSoD that said "Physical Memory Dump ...%" shortly after. Now, the laptop powers on, but the screen stays completely black. My old trick doesn't work anymore. Only the light on my Caps Lock key repeatedly blinks white. The lights on the touch pad and the WLAN key are off which shows that the drivers can't load. I've tried inserting a bootable cd into the optical drive, but it can't boot from there either. I've dismantled the laptop again to make sure I put everything back EXACTLY the way it stated in the manual, but no luck.