Dell Optiplex GXa won’t boot with riser

Hi,
I am working on a Dell Optiplex GXa. I fdisked and reformated the hdd and the computer booted fine. After a second the system froze. Upon attempting a reboot the computer will not boot. I see the fan spin and hear the hdd begin to boot then nothing. When I slide out the lower panel that has the riser board(the board that has the pci and isa slots)it will then boot into windows without any problem. I had let the system sit for a week and when I tried to boot, it booted fine then locked up and I have the same problem as before. I have the restore cd but it does not seem to have a full restore option. Any help is appreciated!!
Thank You, Mark
“Have A Safe Day and Look Both Ways”