X51, no post, beeping

Hi this is Rahul,

I have the same issue that my Dell Alienware X51 desktop won't start and keep making continuous beep. But then it will start sometimes and some times it wont start. I have no idea why it does start sometime and why does not start sometimes. I am a doc and dont know much about comps. My warranty is already expired and I don't think I am smart enough to fix it by myself. What should you advise about it? This was my first Dell and probably the last. This comp is a piece of junk for me now but don't want to throw it away as it was expensive. Please advise