Wireless devices have terrible download but wired computer is fine?

Both of my wireless devices (laptop and iPod) connected to the router at my house have terrible download speeds around.2 Mbps, basically no internet access at that rate. However, the one computer we have connected using a wired connection to the router has fine internet. His computer says he's apparently getting 100Mbps. Regardless of how fast it really is (I don't think it's that fast) youtube videos load almost instantly for him, webpages instantly, game updates download at normal speeds, the whole deal.

This problem began this morning, and was originally working fine all week. My laptop and iPod work completely fine at my other house, but at that house I have Verizon compared to Comcast here. The only thing I could imagine is this. At the moment we have people staying over and we have a total of 8 wireless devices connected to the router (6 iPods/iPhones and 2 laptops) so is that somehow slowing us all down because of all the noise (not sure what the proper term would be) the router receives from the many devices. I don't think this is the problem since I was getting fine internet two days ago, but there were 6 devices connected to the router compared to 8.

So I guess my question about the whole deal is, are there any reasons (I'm sure there's more than one possible problem with these circumstances) you could lead me to further investigating on my own where many wireless devices have almost no internet connectivity while the one wired device is working completely fine.

One more side thing that I really don't think is the problem, my dad gave away our internet password to our neighbors because they wanted to use our internet while they were at the pool because our house is close enough to connect to. I didn't add any possible devices (if they happened to give it to even more people) to my list of 6-8 devices using wireless connection because the pool is only open before 9 PM and I never get on until after 11 PM. However, if they did happen to give it to other people to use at the pool, I'm worried one person who knows how to hack is trolling us since he has easy access into our network. I don't think this is the problem since I used wireshark periodically throughout the day to see what traffic was going through our router and no unwanted IP addresses are using our internet at this time or earlier today when people were at the pool anyway. So I don't think that is the problem anyway, even if this is a thing to do (prohibit only internet connections to a router), but just wanted to throw that out there.

Thanks in advance for any help to solving the issue! Also nobody is doing any big downloads at the house (no torrents or servers running or anything) the only thing the wired computer is doing is playing dota (a computer game if you don't know) basically all day, so he's not exactly hogging the internet connection and no other devices can even get a fast enough connection to do anything, so they're not using the internet much at all. Anyway, thanks!

1. Have you tried power cycling the router? Turn off your devices, power down the router, power it back up again. Wait for it to stabilize. Turn a single device back on, one that was slow before. Check the connect speed. Add each addition device one at a timem, and check the connect speed of each.

2. Log in your router administration page. Try changing the wireless channel. You also can find out how many devices are connected. I would change the network key. Let the neighbors use their own internet service.

Change you DNS server to 8.8.4.4
it will boost your connection

http://expertsdublog.blogspot.com/2013/07/wifi-configuration-with-windows-os.html