:/
I've seen this problem all over the place.. It always leads me to wonder a few things. Like
A) A hard drive is a multilayer compact disc (or other type of disc) stored in a self contained case. A hard drive CANNOT crash. The operating system running it can, and that can inadvertantly delete files. However, a hardrive, if not maintained (and especially so in Dell computers) will gather dust over time, slowing the spin of the disk, and over all slowing your computer as it takes longer to load data. Once a sufficient amount of dust is collected, you should notice a spike in lag, and if you check your disk space left, you'll notice it drops significantly. A 80 gig drive will tend to drop around 3.4 gigs in size. There is virtually no way to recover a drive at this point, and you're best off just scrapping it. Unless you want to rip it open and do some detail work on it, but I'd reccomend that to a professional, as something as simple as oil from the tip of your finger can fry anything inside your computer, especially susceptable are processors, GPUs, and RAM. These devices can fail completely months after touching them, and often results in a completely fragged PC.
And now for...
B) To save yourself all this hassle, go to any hardware store or PC shop, and you should be able to buy a spray-can of air. Occasionally (make sure you know how to safely do this) open up the side panel of your computer, spray the air in all areas, particularily the fans GPU, power supply, CPU, and hard drive, and place a vacuum nearby do clean up the unsettled dust. Doing so should maintain your computer in peak physical condition, ensuring a long life out of all components. This should be done about once a month or two.
Oh, and always rawk an Nvidia card. Forget ATI and don't even think an integrated card will work. Nvidia cards have onboard processors, and a good Nvidia card will supply you with a nice dual RAMDAC at about 350 mhz. Doesn't seem like much, but gaming and video will be many many times better with it. I won't go into why 350 mhz of dedicated processor is so much help, suffice it is to say that an Xbox has a 370 mhz processor. Hopefully, this will never happen to any of us again.