A Keyboard Area (extends out 15")

 28^1/2" W x 16^1/4" D x 4" high

B Tower Area (cut out in back)

9^1/4" W x 17" D x 20^1/2" H

C Printer Area

19^1/2" W x 17" D x 9^1/2" H

D Storage Area (has hole for wires)

19^1/2" W x 17" D x 11" H