Sean’s note: If you’re referring to installing a new hard drive in your system, or connecting one via USB, there’s a good chance that it simply isn’t formatted. You have to go to the Control Panel, go into Computer Management, find the Disk Management tool, and locate it in the list of disks on the bottom pane — then you can initialize it and format it for use with your machine.

If you’re talking about CDs or DVDs, there could be a few things going on here. You can’t play DVDs in a CD drive, so if your machine is older you might want to check if you have a DVD or a CD drive…if CD, anything that’s on a DVD will be unreadable by your machine, and you’ll have to upgrade your drive to a newer DVD drive before you can read these newer disks. If the drive used to work but it just doesn’t any more, it may be dead or may simply have a loose cable inside the machine.

It’s most likely that one of your drivers got corrupted, so you can try to fix it in a couple of ways. First, go into the Device Manager, locate the drive and delete it…when you restart the machine it should reinstall the proper driver.

If your CD drive was actually up and running we would have said that you can also use the System File Checker utility by clicking on the start button, clicking Run and then typing “cmd” — it will pull any files from the Windows installation CD that are corrupted or absent — unfortunately, this won’t work if the CD drive doesn’t work…ooops. If you can borrow an external CD drive from someone, you may be able to use that drive for the Windows source files instead.