The only thing that is slightly unusual in my box construction is the curved front corner, I used a piece of 1 3/4 inch PVC as a corner
I did this because I didn't want the case to be unnecessarily wide, and the hallow pipe allows the tower to slide right up close to the front without hitting a rounded corner piece.
I used hot glue to hold the corner in place, and I recommend you cut the pipe "oversize" to allow for your table saw blade thickness.
The sides of the box are thicker than the pipe which was handy so I cut a rabbit down the edge to match the thickness of the pipe.
The top bottom and front are all Baltic birch plywood 9 ply, I made the sides over lap the top and bottom because I didn't want and seems to show when I skinned it up.
There is a rabbit on the front panel just like the side to accommodate the PVC 1/4 round.
A pin nailer held it together while the glue set..