Dell laptop startup problem (Plzz its urgent!)

Hi. I have a Dell Inspiron core i5 and its been working perfectly for 2 years now until recently...when i turn it on a black screen shows and it makes like a 'bip bip bip' sound nd does not start i.e the dell logo does not even appear...i have to shut it down (by pressing the power button) and then start it up again (sometimes once other times several) for it to start up properly. Once it boots normally, everything is ok for the whole day but once i shut it down at night and start it up in the morning: same prob again. Anyone can help me plz? (Its Urgent!!)