When I turn on the computer it sounds normal and the usual tone after about 2 minutes. But screen doesn't come on. The fan is working and the hard drive light is blinking. What is problem?
If it doesn't say "No Signal" on the screen, the monitor is probably faulty. You can confirm this by trying a different monitor on it that you know is not faulty (try and borrow one just to test on your PC). If that one works, you need a new monitor.