Projector is not projecting in straight lines

I have just bought a used Toshiba projector on Ebay.

There is a problem. The projector is projecting a diagonal picture on the screen. The projector is not projecting in straight lines.

Is there anything I can do to get the picture in straight lines?

regards

I am sure someone will have some advice to share

What's the model number?

its Toshiba TDP-S25

Think that's in the settings on your projector cos it's supposed to be able to do that, if you haven't got the manual, you can download it from here.
http://www.toshiba.de/Projektoren/re..._s25sc25_e.pdf