This a probelm with recharging the battery

you must be new to laptop repair.

parts don't interchange at all, just the HDD If lucky and if the rear HDD actually word this old..
HP Laptop not stated, so....
better is desktops with ATX parts inside, that fit.
The screen dead, battery out and only AC power most times.
the CCFL backlamps dead more are this old. 99% NOW.
your PC is 11 years old (2008) and has CCLF.
acer.com now owns Emachines, just incase that helps,
my guess is Acer when they bought emachines in 2007
renamed it to Acer D620 and added LED back lamps.
some time later.
ahhhh I see your angle YES HP has D620 to, called lattitude
and is not related at all. HP is usa, acer is china.
the D620 came in many sub models.d620-nnnnn
the nnnn means they are using different features for sure screens.
so.... there is no answer and the Acer.com seems to forget the PC exited. but I can't guess the brand name, like Aspire or?

Press ALT+F10 at the Emachines logo. Hope this helps.

My YouTube

Click Here Live Tech Support

Go to this like http://support.emachines.com/em/driver/nb/d620.html
hope this problem solve here...

Remove the main battery and charger from the laptop, press and hold power for 60 seconds, if this fails the motherboard has major issues and should be checked by a technician.

ther are screws everywhere that you will have to find, you should google your problem untill you get the help your looking for

its broken, if less then oen year old call acer and get a replacement

acer owns emachine.

Go to Ebay, (Computers and Networking>PC Components>For Laptops and Notebooks>Screens,LCD Panels>Emachines D620)

Or here is a website I found,
http://www.screentekinc.com/eMachines_D620-5777--14.1-inch--1280x800-wxga-laptop-lcd-screen.shtml

Here is information on removing the old LCD screen,
http://www.sparepartswarehouse.com/LCD-Removal/laptop-lcd-screens-repair-removal-instructions.asp

Another one,
http://www.screentekinc.com/lcd-removal-instructions.shtml

Link to your users guide:
http://support.gateway.com/emachines/Mobile/2008/eMachines/eMD620/emd620ul.shtml

Hi - i've ran a D620 now running a D630 and yes the battery life is extremely poor even when the battery is new.
The option above will give you extra - you can also buy a moduler battery that will fit into the CDROM port which will give you even more!
http://www.google.co.uk/products?hl=en&q=d620%20modular%20battery&cr=countryUK%7CcountryGB&um=1&ie=UTF-8&sa=N&tab=wf

or ebay is your best bet...