I have a Dell i7 lappy sitting in my closet for several months that
seems completely dead. No lights when plugging in AC adapter, no
response to the power switch, nothing. The AC adapter has tested good.
It's out of warranty.

I didn't have time then to see if it was worth fixing up, but I have a
use for it at this point and would like to see if I can get it running
again.

Most of the laptop diagnosis texts I've seen online are outdated or
simply not very good. Can anyone point me to a reference on where to get
started when diagnosing this thing?