It's always a pain when you start using the Internet and it feels much slower than normal. This could be due to a range of reasons, for example it may be a busy time of day (when more people are connected to the Internet in your area, the telephone wires struggle to cope and you unfortunately get a slower connection speed). But it is also possible that someone may be connected to your wireless router, stealing your wifi and slowing you down.
Here's how to find out:
Look at your router. First you have to look at your router and on it, there are several lights, usually one to show there is power, and one to show that you're connected to the Internet, and the third light that should be lit is the wireless.
If this third light is solid when all of your own PCs are off, then you can rest assured that nobody is stealing your Internet at this particular moment and any problems with speed are probably your Internet Service Provider's fault. There is nothing you can do apart from phone them up and complain. (But read on if you want to know how to make your wireless secure.)
If that light is flashing, then don't worry, there is something you can do about it. First turn on your main computer and wait for it to load up. Once it has and you've logged in and it has loaded again, open up Internet Explorer or Firefox (whichever browser you use) and type either this number "192.168.0.1" or "192.168.1.1" depending on which router you have.
Now you need to locate the tab that says "Attached Devices" or something similar. It will bring up all the computers attached to your router and ones that have recently been attached to your router.
It should also give you the option to remove that person from your router. But this will only disconnect them for a short while...
Now you need to set a password on your router to stop people ever being able to gain access to your Internet again.
To do this either go to the Tab "security" or "setup," and choose either a "WEP Key" or a "WPA-PSK." If you have the one I have highlighted in bold, choose that, as it is more secure.
Now set a key you will remember and write it down right away! Now before you do anything else, this will very temporarily disconnect your wireless, and to get back onto it, you will need to configure your wireless with the password you just typed.
Now click "Apply" or "Save" and your router will reboot.
Do this part after you have been disconnected. Double click on the little icon of the wireless desktop in the bottom right corner. It should have an X in front of it, select your wireless network and then type in your password, and then confirm your password. Now you should start connecting and you are now safe from anyone trying to steal your wifi!
Hope this helps. I have tried to give you has much detail as possible but please leave comments if anything is confusing or needs updating.
----- Hyatt was here -----