Someone please help me! I know nothing about computer.. It just happened couple nights ago, I was doing my work with photoshop and turned off the computer for a night.. then everything got messed up.. the computer got really really slow, the white screen with gray apple in the middle and that spinning thingy on the bottom lasts for 30 min, then there's welcome screen (something like welcome to OS X i guess). but usually there's loading bar, but not anymore. then it's just blue screen.. mouse doesn't work, and nothing happens. now i'm trying to reinstall OS X, but the installer can't find a destination disk. i went to disk utility.. the volume is 27.95 GB TOSHIBA, and under there there's supposed to be Macintosh HD volume, but it's gray.. it says Macintosh HD is not mounted. so i went to first aid, verified disk and repaired disk too, and it said 'keys out of order.' i don't have any important file in my computer so i don't mind erasing everything in my computer.. is there anyway to fix this problem?? (I'm sorry if what i wrote is just random and doesn't make sense.. but i really don't know anything about computer..) someone please please help me!

try to get a disk of diskworrior and try running it. that waht i do when ever i get a major problem. works all the time.