Try the following to see if it is a Windows problem (driver) or a physical hardware problem (a bad drive). Reboot your computer, press DEL, F1, or whatever to go into your systems BIOS settings. Find the page that shows your hardware and see if your drive is detected. Make sure that all drives are set to AUTO. Save and allow the machine to reboot. When booting, notice the drives that are detected...press the PAUSE button on your keyboard to stop the boot process if you can't see them as they run by.
If you see the drive, then the drive is OK. If you don't see it, you either have a bad drive or you may need to check the jumpers on the drive (they tell the system whether or not the drive is a Master or Slave). CD drives are generally set to Slave but if you have only one Hard Drive and one CD/DVD drive, put your hard drive on one IDE cable and set it to Master. Put the CD drive on the other IDE cable and jumper it to Master.
If your drive is determined to be good before you go into Windows then allow your system to boot into Windows. Remove the device in Device Manager (you may have to be in Safe Mode) and allow your computer to find the hardware again. This may require a reboot or two.