Could you please let me know the version of Lightroom installed on your computer ?
Also which operating system are you working on, Windows or MAC ?
I have Adobe Lightroom CC 2015
MacBook 10.10.5 OSX Yosemite
Please follow the below steps.
Go to Lightroom Preferences from the Edit menu
Click on Performance tab
Uncheck the Graphics Processor
Let us know if that helps.