They usually check the usual like the memory chips are plugged in and a few other things. I'll agree with them here. It needs repair.
Just in case, try the generic reset noted at the Welcome Thread. Here's the link.
http://www.cnet.comhttp://www.cnet.com/forums/post/30c241c5-dd8b-4d73-b08d-c6e15897fe5f/
HELP! My Dell Inspiron 15 3521 has a black screen and just makes a constant beeping sound when I try to turn it on. The fan starts, then immediately shuts off, and the computer beeps. I took it in to Geek Squad, and the technician had never seen such a thing, and said it must be the motherboard. I have hardly used this laptop, but it is now out of warranty. Any ideas of what I might check? I am an optimist, maybe it is something easy to fix. Thank you for any advice you can give.

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