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)