using COUNT(*) on two columns

I have two columns:

screenWidth
-----------------
1.) 1600
2.) 1600
3.) 1600

screenHeight
----------------
1.) 1200
2.) 1024
3.) 1200

Instead of doing a count on just column screenWidth, I want to do a count on matches for both columns.

So in the above example, the results would show as following:

Screen Resolutions
------------------------
1600 x 1200 (The count would be 2)
1600 x 1024 (The count would be 1)

Is this possible, and can someone give me an idea how it might be accomplished?

Thanks

SELECT screenwidth, screenheight, count(screenwidth) AS "expr1"
FROM Table1
GROUP BY screenwidth, screenheight

The code above will display:

1600 1200 2
1600 1024 1