I have the Lenovo G50-70 Laptop that randomly goes to sleep-(screen goes black and when I press the space bar it goes to my lock screen) when I am using a transcription software Express Scribe and I have also tried downloading other transcription softwares and the same thing occurs. I noticed it happens in conjunction with Microsoft Word. I have Googled a few soluctions and it appears it could be a driver issue, however when I have updated the driver through the Lenovo site it tells me no driver issues detected. I contacted one of my friend name daniel working at geek squad appointment schedule he suggested to do clean reinstallation of windows on my laptop. After doing the same the problem is resolved as of now.