how do you put an image on a face?
 

I am making a computer, but i dont know how to put an image on the screen?

Hard to explain.

Go to www.mtmckinley.net and download his uv'ing tutorial.

For any old face or object, you select the object(s) you wish to texture, create a material (blinn, lambert, phong, whatever) and beside the "color" attribute, there's a little arrow pointing right, click it, then a big list of crap will show up, like marble, mountain, checker, etc. Click file, then link it to your texture. (I tend to like to use jpgs for textures, though I'm sure it can take quite a few formats.)

I'm guessing it's polys going by what you said in another post about using polys. You should be able to either map your UVs (Edit Polygons --> Texture --> then either auto mapping or plain*something or other i can't spell) then goto Window --> UV texture editor and click file --> UV snapshot. This will save an image of your mesh layed out flat that you can paint textures on. Then just assign this image you painted onto to your material like Phopojijo said (hold space bar click materials --> assign new material --> Blinn, then click the checkered box next to color, then click file then just browse for the file you want).

OR

Easier this way, Just select the faces that make up your screen, then just add a material and use a screen grab for it's color.

I would do a quick tutorial for you but i don't have access to maya here to take screen grabs. If your still having problems in the morning i'll post one then. :)