You're ready to stream the latest episode of your favorite show. The smell of popcorn permeates the room, you're settled in your favorite spot and everything is perfect. But when you fire up Netflix, frustration sets in. The video is fuzzy and keeps pausing.

Maybe your Internet connection hit a temporary speed bump. Or maybe it’s something else…. Maybe your neighbors are tapping into your Internet connection, sucking up valuable bandwidth and leaving you and your gadgets with just leftover crumbs of capacity.

How do you know which one it is? And if someone is stealing your Internet, what can you do about it?

Catch the Internet thief

Start by taking stock of your network. Log in to your router and check the section that shows the gadgets that are connected to the network. Check your router's manual for instructions on logging in. If you can't find your manual, download a digital copy here.

If you want an easier solution, you can grab the aptly named Wireless Network Watcher, a free program that gives you a list of gadgets connected to your Wi-Fi network.

Once you have the list of connected gadgets, identify the ones that belong to you. Your computer’s name should show up in the list. Your tablet or smartphone should have the manufacturer or operating system name in there somewhere. You’ll also see streaming video gadgets and video game consoles.

If you can't make heads or tails of the list, simply turn off each gadget one by one (or just disable their Wi-Fi) to figure out what’s what. Take a screenshot or write it down for future reference. When you find a gadget connected to your network that doesn't belong to you, there’s the culprit.

You might need to check back a few times if the Internet slowdown is random. The culprit might be using your Internet only infrequently.

Stop an Internet thief

Even if you spot a rogue connection, you won't be able to tell exactly who is connected. You could barge into your neighbors' houses to check their gadgets' names and MAC addresses – but, for the record, I don't recommend doing that.

Fortunately, you don’t have to. Encrypting your Wi-Fi network will usually be enough to keep intruders out. Click here to learn how to secure your Wi-Fi against intruders.

In fact, you should secure your Wi-Fi network no matter what. There are too many horror stories of criminals using someone else's Wi-Fi in hacking attacks and of perverts trading illegal images. As the owner of the Wi-Fi, you'll have to straighten things out with the police if that happens, and it won't be fun.

If your network is already encrypted and someone still snuck on, change your password immediately. Then keep an eye on things to see if they manage to get on again.

If they do, it's possible they got into your router and set up a backdoor. Reset your router to factory settings (check your manual for instructions) and set it up again from scratch. That means changing the default password, enabling encryption, picking a new SSID and turning off any remote management features.

Note: If you change your encryption password, you will need to update the password on all your gadgets before they can connect again.

Other causes of a slowdown

If you go through these steps and don't see an unauthorized connection on your Wi-Fi, and your Internet is still slow, then you'll need to do more troubleshooting. Test your Internet speed to see if it matches what you're paying for. Try running the speed test a few times with your computer both plugged directly into the router and over Wi-Fi.

If your Wi-Fi speed is way slower than your Internet speed, disconnect all but one of your gadgets and try it again. It could be that you have too many and they're bogging down the network. If that's the case, you might need to upgrade your router to a newer model that can handle more traffic.

Otherwise, call your Internet provider and express your concerns. You might be due for a modem upgrade, or there could be another problem on the line. If you do need a modem upgrade, learn a handy buying trick that can save you money in the long run.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com. Kim also posts breaking tech news 24/7 at News.Komando.com.