XPS L502X won't boot up

I have a Windows 7 XPS L502X that turns on but will not boot up. All I get is a black screen and then when I press the power button, it shuts off. What can I do to fix this without taking it to get repaired? I no longer need it and would like to get it to boot up so I can check for files I would like to keep before I wipe it (it's just sitting under my bed collecting dust). Any help is much appreciated.

Thanks

Steve