[LacrimansTaurne]

Something similar happened to me. My monitor was working fine, but it said it couldn't detect a signal from the computer. I checked the video card and made sure everything was connected properly. Afterwards I turned it back on, and got the same message along with my PC beeping. I replaced the video card and it still kept beeping, and eventually it would turn itself off. It wouldn't make the sounds it normally makes loading Windows either, so I knew it wasn't the monitor causing the problem. Sometimes I could get it to work, but it wouldn't detect the CD-ROM drives or floppy drive or some of my RAM, and would just reset itself randomly. It turns out that the motherboard had become defective, due to overheating from a faulty power supply I had to replace about a month before.