Creating Windows XP style icon for PC cabinet

Start by creating a rectangle using rectangular shape tool.

Double click the layer to open layer style window. Apply layer style with the settings shown.

Create a rectangle using rectangular shape tool. Move this layer below all the layers in layer order in layer palette.
Create a rectangle using rectangular shape tool.
Double click the layer to open layer style window. Apply layer style with the settings shown.

Create some more duplicates and place as shown.
Create a duplicate of the lower rectangle, scale down and change gradient overlay.

 

Create two small rectangles using rectangular shape tool. Place as shown.
Create sign 3 shape using custom shape tool.
Double click the layer to open layer style window. Apply layer style with the settings shown.
Create a circle using elliptical shape tool.
Duplicate the layer and scale down a bit.
Double click the layer to open layer style window. Apply layer style with the settings shown.
Create some duplicates, scale down and place as shown.
Create a rounded rectangle using rounded rectangle shape tool. Double click the layer to open layer style window. Apply a black to white gradient in gradient overlay panel.

Create another rounded rectangle using rounded rectangle shape tool. Double click the layer to open layer style window. Apply a red to white gradient in gradient overlay panel.
Select and merge all the layers. Apply some drop shadow.