Agreed.
You should IMMEDIATELY backup your hard drive. If you have a Western Digital hard drive (even USB), use their free Acronis True Image software and make a backup of your entire C-drive (assuming it's your Windows drive) or other drive if not.
Use the VALIDATE feature in Acronis True Image.
There are other methods of backing up.
Example:
1) Backup to a secondary hard drive using Acronis TI (or Windows 7 Image backup)
2) obtain hard drive diagnostic software and check it (not sure if it's 100% reliable)
3) RMA your hard drive if it's faulty (Western Digital has an option to send the drive immediately before you send yours)
4) RESTORE the backup or CLONE to a new hard drive
Also:
1) run MEMTEST for a couple hours (memtest.org I think)
2) your software may be corrupt. if so, carefully plan how to reinstall Windows (backup e-mail, data, passwords etc, install Windows, install main chipset driver from website for motherboard, then other motherboard drivers, then remaining driver like video drivers, then Microsoft Updates)
Backing up:
Make periodic backups (at least once per month). For $50 you can get the full version of Acronis which can update a backup of your system's software as little as once every 5-minutes. I have mine set to daily backups. These backups go to my second desktop drive (2TB WD hard drive). In the future if your system gets a major virus, other software issues or simply fails you can easily RESTORE everything.
Make three backups:
1) make the first backup after all your drivers and Microsoft Updates are finished AND you have Activated Windows (you never want to RESTORE an Unactivated copy of Windows because it then requires you now Activate again and there's a limited number of Activations per copy. OEM copies have three Activations I think.)
2) Always keep that first backup and make a second one once all your software is on.
3) Make a third backup every month (unless you automate it more frequently)
*It's really worth the extra money to buy Acronis and set things to automatically backup to a secondary hard drive.
Good luck. I hope this helps.