Dell Studio 540

One long, two short beeps.
1. Video Adapter (any type)
2. Video Memory (if used)
3. System Board
4. Adapter Video Memory
5. Bus Adapter
6. ACPA /A Adapter
7. Power Supply
Check again, how many beeps and then see in this
http://www.computerhope.com/beep.htm

and http://ohlandl.ipv7.net/errors/Error_Beep_Codes.html

Is the Power Light blinking with color=Amber?

If yes, could be a bad motherboard.

Check attached file, It will help you definitly.

I think system board problem.
Untitled.png

Mez,

I agree with the direction you are going, however I would not reinstall the devices once removed.

Disconnect everything from the board (This includes Hard drives) with exception of a single memory module, the power supply, and graphics card and keyboard and mouse.

Boot the computer up and let us know if you are still receiving this beep error code. if you are still receiving this error code then remove and reseat the CMOS battery. If this doesn't correct your issue then there is a good chance that your motherboard is gone.

If it's an Award BIOS, then one long and two short beeps is the video card.  Have you tried this card in another machine?  Did you try reseating it?

if you need more help for troubleshooting the problem, use the minimum setup as described in my article :
https://www.experts-exchange.com/Hardware/Components/Motherboards/A_1945.html                  (Short-overview-of-how-to-troubleshoot-bad-hardware-when-a-pc-does-not-post)

in case the disk has problems, this can help also :
https://www.experts-exchange.com/Storage/Hard_Drives/A_3000-The-bad-hard-disk-problem.html