I think my directv dvr is interfering with my internet connection when it's plugged into my router.Anyone help?

I have Cable Internet to a modem, then goes to a router which has my 2nd computer and the directv dvr plugged into it hardwired to those devices with ethernet cords, Internet was working fine until a few nights ago I went onto my second computer and deleted my avira antivirus and added Glary utilities, I was going to download some kind of antivirus from windows but gave me some kind of error so iI changed my mind, then the next day, my main computer didn't work, I did all troubleshooting, reset modem and comp and comp check cables, then called internet company they said that my router was bad, so I hooked up a different router and brand new ethernet cables also, on bottom left of pc the thing that shows you if its connected to internet, showed a ciorcle like it was trying to connect, then a red x, kept on doing this, disabled lan made sure the autamattically detec fileds were checked, then enabled, the internet worked for a minute, then kept with the circle and red x, when I opened naetwork and conenction center said public setting, so I changed to home network, worked for a few minutes, then stoped working, then everytime I would try something new, it kept going back to public network (which I don'yt want), I eventually hooked my main pc to computer, but I wanted to use it, and I heard somewhere dvr might mess internet up, so I unplugged dvr, and reset, now works fine, for a couple hours already, is there a way I can fix this? Is this whats causing the issue? Any ideas, I'd like to have access to internet on dvr also.I even restored pc to previous date before this happened and It didn't give me my antivirus back or it still didn't work.Thanks