There are shops willing to do these types of recovery when stuff mysteriously disappears from your hard disk drive, but only at a somewhat high price if you want your stuff restored. Unless you have some stuff on that computer you don't want people to find out about :toungesmile:, you could always give it a try. And yeah, depending on what hardware your computer is running (more like how weak at times), if a program doesn't close properly, you can end up with wiped out files if you're not careful when you start your computer again. (Happened to 300 gigabyte worth of files before last time I recalled...) If you remember the time the wipe out occurred, you could go to administrative tools and check the error log to see what happened or what conflicts might have happened.
And what square-enix, newegg.com is definitely a nice place to look for a new hdd compare to Bestbuy. If you have a Fry's nearby, there might be a good deal or better than what you can find at Bestbuy, at least for me anyway.