RE: Inspiron 3521 won't start up
Thank you for your reply and sorry for being late to answer.
To clarify my previous answer, if I start it up with no RAM at all then I get no response at all (neither the 'popping' sound, or the usual BIOS beeps).
I don't have a spare HHD, but I've booted up with no HD (having put the RAM back in!), and I still get the same popping sound. So the noise itself is coming from the motherboard.
Can I assume the next stage is a replacement MB (assuming it's economically viable)?
Thanks again for all your help.