To allow the wood floors to be refinished, I removed the storage unit that was in the closet of the Computer Room. This left an empty closet, with some rails and brackets for shelves down the left side.
We wanted to do the same sort of storage unit in the middle, but with just shelves -- no drawers. And also put shelves down the right to match the ones on the left. So we bought a ClosetMaid 25 inch Wide Tower for the middle (Home Depot, $167.98).
This came as a flat pack of shelves and sides and had to be put together, like from IKEA. I modified the two side supports to allow for our baseboards and slid it into place.
Next we took out the old wood shelves from when the house was built that were hidden on the right side of the closet. They were supported by 1x2 pieces nailed onto the walls.
We then had to patch the sheetrock and paint the walls to match the wall color. Then we bought and installed new shelf rails, to match the ones on the left side.
We also bought 6 new white wood shelves and twelve brackets to support them. Home Depot, $196.81)
We put the brackets on the rails, and then the shelves on the brackets.
The closet is about 8 feet wide. So a 3 foot shelf, the 24 inch storage unit, and another 3 foot shelf fits in pretty well. There is about 1/2 inch of space left. We jammed 1/2 and 3/8 square dowels between the shelves and the storage unit on the right, to fill the gap and hold everything rigidly in place.
To finish things off, we added a third vertical rail in the corner on the right, so that the shwlves were stable.
On the left, there are no studs to put a third rail on, so we drilled holes in the side of the storage unit and put pegs in them to support the edge of the shelves.
We also raised the lowest shelf in the storage unit to allow our rolling cart to fit in the bottom of the storage unit.