I was walking up the stairs with it ON, and and I dropped it on the floor. It wasn't a bad drop, but it still won't go past the start up screen. The little floating lights when its starting up don't appear. I know I have to get a new hard drive. I've broken computers in the past so my parents weren't happy. Will it cost much? Is there anyway I can fix it without taking it somewhere? Where's the hard drive in the computer, could it have been knocked loose?
Dropped my Lenovo thinkpad?
I bet you damaged your hard drive. You should consider an SSD instead of a hard drive, they're almost shock-proof. You might also consider a desktop, which are a lot more difficult to accidentally destroy.
Download a Live-CD Linux distribution, burn it (or use unetbootin to save it to USB stick) and check if you can view your hard drive files. It's possible it was only partial damage.
FYI: Hard drive heads float on top of the disc, the distance is so small, a particle of smoke is larger than the gap! Next time, shut down or put the laptop to sleep, which parks the drive heads. Pricier laptops have a sensor that park the drive heads when the laptop tilts or fall.
It's very impossible for a HDD or SSD to just "slip out" from its chassis.
Anyway, a new HDD would cost around $100 (depending on how much storage you want), then you would have to reinstall tour O.S with it. Alternatively, you can try to recover files from your damaged HDD by accessing Command Prompt from the ASR, then accessing notepad to navigate through the user interface.
Sometimes a dropped HDD can be accessed this way (corrupt partition table or MBR), but not always.
Maybe it isn't just your hard drive… Try a bootable dvd/cd/stick see if its working.
New hard drive can be $70-$100, and you'll have to reload the operating system on it as a new hard drive is blank. There's no way that it could've "slipped" out.