Laptops often don't have contrast controls (which means that their displays are usually far less than optimal). To find out if yours does, right-click on your desktop. On the desktop I'm using the available options then include 'Graphics Properties'. Clicking on that, and then on 'Color Correction' enables me, among other things, to tweak the brightness and contrast. You
might have something similar available to you on your laptop, so take a look.
If you've not got a contrast setting, you should still be able to change the brightness. Most laptops have got keys with 'brightness up' and 'brightness down' symbols on them, usually in a colour such as blue. Here are some examples:
http://www.notebookcheck.net/fileadmin/_migrated/pics/Vaio_fw_51_bildschirmhelligkeit_03.JPG
https://bd23.https.cdn.softlayer.net/80BD23/142.4.51.106/blog/wp-content/uploads/2012/08/acer-laptop-adjust-screen-brightness.png
http://www.pc-xp.com/wp-content/uploads/Brightness.jpg
To get them to work, you need to press them at the same time as the 'Fn' key (which will be in the same colour).