Act Fast- There may yet be hope!
If your hard drive starts to get very, very slow, or you hear even one or two clicks every so often, turn off your computer right away! You need to use the time the drive has left to get the data off. You don't have long. If you have your data backed up and there is no need to retrieve the information on the hard drive, then the solution is simple: replace it. If you must retrieve data, here are some things you can try.
If you are unsure of your ability to follow any of the following steps, stop now and take your computer to a professional.
1) Turn your computer on its side and turn it back on. Although unorthodox, in cases of physical shock (specifically, the laptop/car incident mentioned above) it is possible that it will help. It might not do anything, but it's worth a quick try.
2) This step is much more involved. Go to the Trinity Rescue Kit home page and download the .ISO image of the Trinity Rescue Kit. Burn the .ISO image to a CDR. You'll need to have the computer networked with a cable to your router. You'll need a second Windows PC also networked either with a wire or wirelessly. Boot up the failed computer with the TRK disk you just made. When you see the boot menu, just press Enter. When the next menu comes up, select "Run a Windows File Server", and press enter. Then select "Run an unsecured fileserver in guest mode". Write down the IP that it shows you, such as "192.168.1.136".
Now go to the other computer. Open up "My Computer" and in the address bar at the top type in \\192.168.1.136 (or whatever IP you wrote down) and press Enter. Navigate to your hard drive and the folders you need data from. Copy them to your computer right away. When you're done, you can safely turn off the failed computer.
3) Get Data Back is great software option that may be able to recover your files. It is free to try as a demo, but you can only retrieve the data if you buy it for $69 or $79. If you have Windows XP or newer you'll need the NTFS version ($79). Older machines may need the FAT32 version ($69). You'll have to connect the hard drive to a host computer through either USB, IDE, or SATA.