Hi, roshan. What have you been doing with it before it won't turn on, or, it just as you said suddenly won't turn without any symbol? Some bad apps improper running would lead to iPod won't turn on, so check what apps are running on your iPod. If possible, force quit it and then try to restart your iPod. Well, if this didn't work for you, you can try other software/firmware restore to reboot your iPod. DFU mode and Recovery Mode are most commonly used in this situation. For my personal experience, I prefer Recovery mode to DFU mode because i can easily force my iPad into recovery mode with the google recommended tool ReiBoot.
Thanks for brisbane wholesalers' knowledge for iPhone error 3. If you fixed the network problem, you can use a quite easy and quick tool to exit iPhone recovery mode screen without plugging into iTunes, just one click to enter or exit recovery mode without effort. You may know the tool called ReiBoot, which is now downloaded by most of iPhone users to fix iPhone dead screen issues. Get it from google if needed.
Maybe the best and easiest way to put iPhone, iPad, iPod and all iOS devices out of recovery mode is to use Tenorshare ReiBoot, a free and safe tool provided by Tenorshare Software Company. Get it from google.
If it is not the lock code, maybe it is the iPhone backup password. Have you set such an encryption on your backup while you sync your iPhone to iTunes? If so, try the backup password. However, if it won't let you enter passcode, you can use a toll called Tenorshare ReiBootto put your iPhone into then out of recovery mode. This may fix the stuck screen. Note: Don't hard reset your iPhone because it will erase all iPhone data and settings.