Lag Issues over a Network

[Arrmani]

So first of all, the internet comes from Comcast in one of the triple play things. I'm not sure how fast it is exactly, but I don't think its the problem.

When I'm home by myself, I don't have any lag or loading problems online or in games. When my dad comes home and gets on his computer, everything slows to a crawl and usually I can't connect to online games.

The first problem I thought was he was either downloading or uploading stuff all the time limiting my bandwidth, but it seems like whenever hes just surfing the internet, it goes to shit.

My questions are, could it be the modem or routers are bad? I'm not sure how old the routers are, but I guess the modem is maybe 3 years old from when we first got Comcast. The next problem I think it might be is, for some reason, there are 4 routers and a modem making up our network. I honestly have no idea what all they're used for, as I only run 2 cables upstairs for my computer and Xbox 360, and my PS3 is wireless or uses the Xbox 360 cable.

Any advice is appreciated, though if the problem keeps up when I try running a new computer, I'll see if I can get him to clean up our network stuff.

[Cephius]

Could be a virus or something on your dad's computer that's flooding your network with packets when he's online. Try running some scans on his machine?

[Punices9]

I have had a similar problem with my Comcast service as of recent. We have the Triple Play as well and have been experiencing slower internet speeds in the last few weeks or so. I was wondering if Comcast was somehow responsible for this since they probably want people to upgrade to Xfinity.

[xopher]

Learn2Wireshark

[Arrmani]

I was thinking it might be a virus because he said before he was trying to get rid of one, but I figured he formatted his hard drive to get rid of it. I thought my machine had one because I have a program called csrss.exe that uses a lot of memory, but it doesn't seem like mine runs slow all the time.

Another thing I thought could be a problem was me running 2 monitors from a not so good video card, but I didn't think that would make something run slow, just occasionally some display problems.