Steam games losing connection and lag spikes

So I just installed steam and I have CS:S, Garrys mod, mw2, and TF2. All of the games keep giving me the error message in the top right of the screen: "Connection error: Retrying 30s" and it counts down. Once it goes down to 5s, it re-connects and works for a few mins, then does it again over and over. I'm pretty sure this is a problem with the computer or steam because I play xbox 360 over wireless as well and don't get this problem at all. The weird thing is that when this happens, I can't even use my browser. It's like the games shut down the router for 30 secs... I use avast and I've also seen that Windows firewall is up. What could be causing this?

My other question is about lag spikes in minecraft. When I first started playing, the game ran smoothly on far render distance. Now it won't even run at a steady fps at normal render distance. I have to set it to small render distance and even then, I get occasional lag spikes. Why would it do this? Is it because I've been mining and creating things? I wouldn't think so but who knows. I've been downloading and installing a few steam games since the 1st time I played minecraft but I doubt that has to do with it either. I was getting a steady FPS even WHILE downloading stuff. Now I'm not and I'm not even downloading anything. Any thoughts on this?

Thanks guys. I appreciate it

 

408 cali, do you have proper ports open for steam on your router?
https://support.steampowered.com/kb_article.php?ref=8571-GLVN-8711

Also do you have any problems when you are just browsing or doing email with steam totally shut down?
Please post back your speeds:
Speedtest.net - The Global Broadband Speed Test

 

I don't even know what ports are and I'm omw to work. I'm writing this on my phone. As for speeds, I checked that already. I'm getting 4.8 mb/s I think. But my xbox ran wireless xbox live fine so I don't think its the internet speed.

 

I'm also having this connection problem while trying to play steam games over my home wireless network with my brother. Whether steam is running or closed, normal internet browsing works fine, but whenever we start a game such as Portal 2 or Supreme Commander 2, we get disconnected a couple minutes into the game. This only started happening about a couple weeks ago; before that, Steam and the games ran smoothly.