Purchased Dell Optiplex 745's,755's and 760's

​Hello Dell,​

​I recently purchased some computers at a government auction which include Dell Optiplex 745's,755's and 760's. I have an excess of over 100 computers which I intend to fix and send to my country Zambia as part of the Charity work I do. Some of the computers are going to go to schools and other organizations that I work with. When I started working on the computers,almost all the computers wont boot past the splash screen to my surprise and cant even go into setup. I have gone through a number of steps to try to resolve the issue but to no avail. Please help me resolve the issue. I have spent so many sleepless nights on this. Upon physical inspection the capacitors appear to be OK-Tried control P at reboot but nothing came up-put in a CD and rebooted but that wont load. I have unplugged everything and started from a clean board but same issue-Very depressing for a tech- I love this product but I haven't slept for a week now. Any help on this would be highly appreciated not only me but by thousands of Zambians. Thank you.​