Amazing Problem, Bother to Me

Today I face the amazing Problem Here . When I am doing Some designing Work from Html,Css By using webstorm IDE at that time my computer just slow down After then stops to work . Then I shut down my computer by pressing Power button . After While When I open my computer and check that design work on web browser all the css files and previous work are not saved there . Then I check the css file there is no any code, It makes me sad . There is the warning in my Webstorm IDE appear as a Load Setting and goes . I have no Idea how to solve it , When I open that css file There is the Null word everywhere .