Object Translations Needed for Each Window Corner

Hi,

I posted recently about this problem but it did not really portray my problem well I dont think.

I would like to know what translations are necessary to place an object at each of the four corners of the screen (0,0) (0,ysize) (xsize, 0) and (xsize, ysize).

I have tried using gluUnProject to do so where the x,y,z inputs would be 0,0,0 for the first corner for example but the output is no where near correct.

Are there any other approaches I could take to avoid gluUnProject?

Thank you,
Jassel41

Fixed my problem sorry for the multiple posts. I was having trouble with the z buffer but fixed it by taking the z coordinate from a previous gluProject call and using it as the input to gluUnProject rather than a random z value.