Dell Inspiron 1100 nothing on screen after bootup

I have a Dell Inspiron 1100 that when it boots and you can hear it running I get nothing on the screen. It gives 3 quick beeps then a single beep. The power and battery LED are lit, but not the hard drive. The hard drive LED flashes a couple times when first booting but then goes out! I have tried this hard drive on an external hard drive enclosure and it works just fine. I can't find this beep code anywhere and just wondering if anyone here has any Idea?

Thanks in advance for any help you can give me.

 

First I would check to make sure the ram is seated properly as well as the hard drive. Make sure all connections are clean
Try hooking up an external monitor if at all possible, may be faulty monitor.
Check the system fan for dust clogg
Failing that you may have a faulty system board.