Some of the most common reasons why an iPod won't charge include low-power USB ports, a damaged charging cable or a broken iPod power adapter. The battery of an iPod could also be faulty, which requires a replacement.
A broken cable is a common reason for an iPod not charging. If the battery isn't charging correctly, then a replacement cable should be used to see if this is the problem. There are also iPod cables sold by third-party manufacturers which may not work with all iPod versions.
If the iPod is attempting to charge via a USB port, then the problem could be that the port is faulty and not supplying enough power. This can be tested by trying several USB ports that are known to work correctly. Keyboards and other devices with lower-powered USB ports are also not be able to charge an iPod.
There are a number of other potential reasons why an iPod battery doesn't hold a charge. If the iPod screen has frozen, for example, then the battery cannot charge. To fix this, the iPod should be reset. iPods also do not support charging from computers using Windows 2000 without extra steps to resolve potential issues.