Navissa,   It could be a couple things, such as that your configuration may require removing the cooling fan assembly. You can find the details on page 114 here.   Let me know if this helps.    
Hi, Since nothing is working on my T620 and its completely dead, I thought about checking if maybe the Front Panel is broken, and reseating the cables might do something. However, I cannot get the Panel out? I watched a video on how to do it, which is just loosening one screw, but that did not work for me. How do I get the dang thing out??? Second question: If indeed my Motherboard is broken, wouldn't there still be power on the front panel? I mean, isn't that what the Panel is for, to tell you if and what is not working properly? Anything helps. Thanks.
PowerEdge T620 Front Panel.