Disconect any external device (like usb sticks, etc) and try again
You can try boot from cd (change boot order in bios to set cd rom first) and press R for recovery console.
Type 1, hit enter, type password or just hit enter if U don't have one, and type
chkdsk /r /f and hit enter. Let it check.
You can try setting your bios to default. (f2 or del at startup)
You can try Hirren boot cd to scan and other stuffs
http://www.tomsguide.com/us/download/Hiren-s-BootCD,0301-32451.html
Some PC's have their own tests at startup, (like hard drive test, memory test) .See if yours has that or not.