sorry to hear you are having this issue.
Here are some possibilities for you to check;
The beeps you describe point to memory card issues, this can sometimes be
caused by dust,try removing the memory sticks blowing out the slots and then
replacing the card/s securely, remove the power cord 1st and take anti static
precautions by grounding yourself on a bare metal part of the case, however
the other symptoms you describe sound like your HDD may have failed,other
possibilities are the psu not providing power to the HDD a bad lead/ribbon
or MB connection.
Here is the beep chart, which one best describes what you hear!
1 short: System boots successfully
2 short: CMOS setting error
1 long, 1 short: Memory or motherboard error
1 long, 2 short: Monitor or graphics card error
1 long, 3 short: Keyboard error
1 long, 9 short: BIOS ROM error
Continuous long beeps: Graphics card not inserted properly
Continuous short beeps: Power error
I can see none of the drives have been found (except the 2 CD drives).
How many HDDs do you have?
What is the Dell model or tag number, providing this information will enable others to help you better.