slightly transparent? that implies its only tranparent by a little bit

i know when i connect a psd file as a texture it can connect to both colour and transparency

go to your hypershade, Windows > Rendering Editors > Hypershade,
find your material that has the psd linked to it,
right click (and hold) and move the mouse down to graph selected

then you'll see the inputs to that material.
if the file node is connected twice to the material node then select the connection that says 'transparency' when you mouse over and cut it (hit delete)

if that doesn't do the trick then i dunno.....