preparaing disk repair stuck

I hello everyone  , 

'm using a Dell Inspiron 15R laptop, operating on the latest update of windows 8.1. When I turned on my laptop today, it was acting fine. When it asked me for the password, after typing it in, my computer froze. I left it alone for a few minutes. When it didn't unfreeze, I decided to manually shut it off using the power button. The power button didn't succeed in turning it off, so I closed my laptop and left it alone for a while. When I opened it up, there was a black screen. I tried turning it on, to no effect; it almost seemed like it froze with the screen off. After a few more attempts of trying to turn it on/off, shutting the laptop, opening it again and repeating the process, it finally turned on. The  Then the Dell symbol popped up again, and beneath it, it said "Preparing Automatic Repair" with a loading symbol. After a few seconds, the screen flashed black, then the Dell symbol popped up again, underneath it there being a loading symbol and the words "Diagnosing your PC." The words then changed again to "Repairing disk errors. This might take over an hour to complete." After waiting two hours, I turned it off and on a few more times, hoping that it would fix itself, but to no avail. I really need to fix this as soon as possible, because I need my laptop to do homework. I haven't backed up my computer, so is there still any way to save the stuff I have saved to my computer?I chatted with MS customer care  . he told me to go for full format of my laptop . earlier boot option menu was coming. but I performed once chkdsk\r cmd on command prompt. but not I am not able to get boot option menu :-( please help me L:-( I dont have the boot CD