If Windows cannot find a hard drive during the installation then you may have a problem with the drive not being recognized in the BIOS or a problem with the hard drive, cable or motherboard itself. I would go into your BIOS settings and see if its recognized there. If its a newer computer then usually having it set to Auto works and it should find it.
If it doesn't show up there then make sure the cables are connected correctly and that its getting power. If its an IDE drive check to make sure the cable is attached properly and not backwards. Usually the red stripe on the ribbon cable should be on the same side as the power connector. You may also want to use a different power connector in case one of them is defective. Also check the ribbon cable connection on the motherboard to make sure its in the right way and not loose. There should be marking on by the connector that has the number 1 on it indicating where the red side of the cable goes since that represents pin number 1.
If its a SATA hard drive then check the connections as well. Some SATA drives have different types of power connectors and others use the same Molex type as IDE drives. The BIOS settings for SATA drives are usually in a different area then for IDE drives.
You can also run the computer with the cover off and see if you can hear the drive spin up during startup to see if its getting power to it. You may also want to try different ports to see if you have a bad hard drive connection on the motherboard.