I do not know what I did but now I can not start up my computer. I had a tv for monitor. I changed that back out and put back in my HP monitor that came with computer. When I started computer I did not notice it had started the chkdisk program. I looked up to see I had 2 seconds to stop it. I did not make it. I found the second disk I added was bad. I shut down computer and removed the second disk. Previously I changed the power supply and the video card. I can start up in safe mode but not normal. It will check for disk and then start up and then the monitor will shut down. No signal shows before it shuts down, This may be simple fix but I do not know. Please help.