There is too much ambiguity to be able to answer the question afaic.
As Zawran says, it could be an issue in the screen setup code, it could be an issue with the texture not being centered on the quad, it could be a view matrix problem or maybe a lot of other things..
Maybe you would rather solve as much of the problem by yourself as you can pot noodle, but as usual you will have to post your code to get the best answer - it saves us time and it's more helpful to others who may run into the same issues as you have.
Thanks.