so, let my just begin to explain my problem. today, i was casually playing world of warcraft but had to go afk for about an hour. when i came back, wow had crashed, but i figured it was just a regular disconnection, which it sometimes crashes on. so i force closed it because i wanted to get online again and continue with what i was doing before. but when i did force close it, the whole computer started to act slow. so i began watching some youtube videos in the wait for wow to start again, but it never did, and eventually the youtube videos stopped loading, and i was stuck on the same page. i could not turn off my computer either for some reason, so i decided to force it to turn itself off with the power button. this might have been a really really bad call, but as i started the computer again, it took way more to for it to start than it regulary do, and when i finally got it to start, i couldn't do anything, because it literally took five minutes to get out of the windows 8 homescreen to the regular desktop. so i forced closed it again, which again, is a bad call, but i was really not in the mood to care. i do regret this afterwards, but it's already too late.
anyways, as i finally managed to start the battle.net launcher again to see if i would be faced with the same problem, i was instead faced with the problem that it didn't open at all. so i went to see what was up with the hard drives, and this is what i saw.


the highlighted harddrive ( D: ) seems to almost be missing, or something. i really have no idea, but i cannot access it. so i did some research, but found nothing which could help me. and yes, i have barely anything left of the C: drive, don't fucking blame me
my ( D: ) drive was at around 400gb left of memory yesterday.
i know no one came into the room and did something with the computer because i were always able to see my room from where i sat, and no one entered it.

so onto the specs.
the laptop is a msi ge70.
read about it here.

i can still access the internet, a few games and do stuff on the computer, but -my- main, not the actual computer's, but the drive i use most and save everything on is unaccessable.

for those who can help, i really really appreciate you to take a look at the case.
thank you for your time.