Dell gx80

well since there was no GX80
I think you mean the GX280?
here is Dell support showing how to remove a HD from a Dell GX280
http://support.dell.com/support/edocs/systems/opgx280/en/ug/sddrives.htm#wp1166677
if you just go to this page
http://support.dell.com/support/topics/global.aspx/support/my_systems_info/manuals?c=us&cs=19&l=en&s=dhs&~ck=anavml

and choose your model or enter your service tag number found on sticker on tower
then you can select manuals
and it will usually show how to remove and replace your parts

hope this helps