Laptop issue

I was using my sisters laptop- and I was on windows and everything started running slow and non respondsive I did a blue screen with the white error message on the screen, with being an idoit, I restarted the computer without reading the total error since it was the first message I have gotten. Now when the computer is started it does not load windows and it first responds no media cable connected then soon after I get a message saying no operating system found, what can I do to recover the problem or can I? Thanks for all your help!!!