PC Booting problem

Question

Hi,
I am having ASUS based PC. It normally doesnot boot up in first go due to hanging I have to restart it many times before it finally boots up. Sometimes while running it hangs abruptly and cursor of mouse and keys of keyboard does not work at all. I have to restart the computer many times before it can finally starts.I got it checked but the person could not do any thing. Pls help
Thanks