Okay my friend I have switched over to my primary computer.
I have several links to offer you.
First the support page for your Dell latitude D620 http://support.dell.com/support/edocs/syst...20/en/index.htm
I am linking you to your service manual, this manual has exploded views of your laptop. http://support.dell.com/support/edocs/syst...en/SM/index.htm
You can download the manual to your computer from the first link I gave you, just click the download tab next to service manual.
Here is another useful link regarding Dell laptops, it might shed a little light on the subject as well. http://www.insidemylaptop.com/category/4-dell-laptops/
Hopefully this information will help you in saving the cost of a costly laptop repair and help you bring your laptop back to life.
Kind regards and thank you for using Bleepingcomputer for help and advice.