Thanks to nukemaster for obtaining picture.
ANTEC 900 Top Removal + 200mm Fan Replacement Guide
1. Obviously turn off ALL components attached to the case (I.E. PSU, and such)
2. Proceed to take side panels off (One is only needed but case is easier to handle)
3. Proceed to unscrew 2 screws (Marked in Yellow in photo) located at the center of the Upper Case (usually visible, but hard to find at first look)
4. Then, push all 4 retaining clips through, NOT alot of pressure is needed on these clips (AKA don't break them)
5. Give alittle tug for upper retaining clips to release (*BE CAREFUL due to CABLES are still attached to internal components and case)
6. Do a 90 degree rotation of upper panel so the fan is accessible.
Replacement of 200mm fan (BIG BOY 200)
1. Remove 3 screws that hold fan in place (Marked by green in photo)
2. Remove 200mm Big Boy fan
3. Proceed to place new fan in.
Reverse order to proceed to "normal" structure.
If this helps anyone, please post!