Ok, to do a bit of diagnosis you will need a small phillpis screwdriver.
First remove the battery and the two screws that hold the hard drive caddy in the case
(hard drive is under the left corner of the computer)
Remove the drive (it simply slides outwards)
Reinstall the battery and/or reconnect the power and try turning the computer on...
What does it do? if it tells you there is "no booth device" press Control+Alt+Del at the same time and next time press F2 as the computer tries to start, if it goes to the bios screen buy a new hard drive and start looking for your physical reinstallation media
If it DOES NOT start next remove the memory/CPU cover (eight screws)
With the power disconnected and the battery removed remove the top RAM module, set it aside, reinstall the battery and try starting it again... Any luck?
If NOT remove the second memory module and temprarily install the first one in the lower slot
and try it all again... (usual caveats about disconnecting the power/removing the battery)
It is important to keep track of which memory module is which, because typically a Dell 1525 comes with 3gb of ram, a 2gb module and a 1gb module, and they seem to want the 2gb module in the lower slot...
Primarily I'm expecting you to find that either the Hard drive died or one of the memory modules is faulty.
Good luck!
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