|Can not close reg cover on Dell Color Laser Printer 3100cn|
I was able to get the back reg cover close and here's how.
The cover slides just slightly to the left and right (very slightly almost not noticable) and occassionally aligns with the ridges on the inside causing it to buckle and thus not close. Try and offset the ridges just slightly and then close.
Also, I noticed a little hook at the bottom of the reg cover that flips up inside the cover. It is roughly in the center bottom of the back reg cover and can be felt from the outside. Flip it up while trying to close the cover. This should also work. I'm not sure if it just gets in the way, but it also helps. Just be careful you don't pinch your fingers.