If you're having problems with your iPod, especially if it seems to be locked up and won't respond, the first thing to try is to reset the iPod. 

Every ipod out there has a reset feature, but most people rarely have to use it, so very few people know how to do it. 

How to reset iPod Classic, iPod Nano, iPod Mini, iPod Video

The reset feature for most iPods is the same:

First, either make sure your battery is fully charged, or to make it easier, hook up your ipod to a power source.

Next, flip the hold switch (or lock switch, whatever you call it) from off, to on, then off again.  Now press and hold the Menu AND Select buttons together until the Apple logo appears.  This might take between 6 to 10 seconds.

When doing this, make sure you're ONLY hitting the Menu and Select buttons.  If you touch any other buttons at the same time, the process won't work.

How to reset iPod Shuffle

First, unplug the Shuffle from the computer if you have it plugged in.

Next, move the switch on the back of the Shuffle into the OFF position and leave it there for atleast 5 seconds.  Turn it back on and your Shuffle should be reset.

How to restart or reset iPod Touch

The iPod Touch is a little different obviously, since it has a totally different interface, and a touch screen.

The first thing to try when your iPod Touch starts messing up is to close the application you're currently using by holding the Home button for 6 seconds.

If this doesn't help, try to restart it.  To restart the iPod Touch, simply hold the Sleep/Wake button until the red slider appears, then slide your finger to the right to turn it off.  Now turn it back on by holding the sleep/wake button until the Apple logo appears.

If restarting doesn't help, try to Reset it.  To do this, press and hold the sleep/wake button and the home button together until you see the Apple logo, which might take a few seconds.

If none of this helps with your problems, you might want to remove any software or other downloads you've installed recently that might have caused the problem.

How to Restore any iPod to Factory Settings

If all else fails, you can always Restore your iPod to factory settings.  You'll probably want to keep this as a final resort, since it wipes all of your data and settings, but sometimes this might be necessary if you have major problems with your iPod.

Restores are done through iTunes, so you'll probably want to make sure you have the latest version of iTunes before you begin.  iTunes should do this on its own, but you can check yourself by going up to Help - Check for Updates.

Every iPod can be restored the same way.  Hook up your iPod to your computer and open iTunes.  When your iPod shows up in the Source list, click on the Summary tab.  From here, simply click on the Restore button to start the procedure.