You turn on desktop computer. You can heard it starting to work and windows start to load, but your screen doesn’t show anything or “no signal found”. This can happen for many reasons. If you moved your computer recently, please check all your cables. They can be loose slightly and did not send proper signal. If cables are all ok, you should try to connect Screen to another computer. Maybe your monitor is faulty?
Sometimes screen shows nothing because of faulty graphic card or other hardware. If steps mentioned above did not solve your problem, you should contact professional computer repair technician.