this dude on xbox live was mad we were beating him so he said he is going to send something through to our ip adress to slow down the computer. My question is is it possible and if so how do I fix it?
Please answer as soon as possible.

no

Depends...

Do are you behind a router/firewall.. then no, not the computer or xbox

However,

He could potentially DoS yer internet connection which would slow you down a bit.. the internet that is.. potentially that is..

I'm really not familiar with how X-box broadcasts and IP address. How would he get it in the first place to launch a denial of service attack? If he is successful with it then it will slow down your entire household internet connection. IF he's stupid enough to launch that attack from his own household IP address he's an idiot - you can report him to his ISP at that point. Hopefully he's not smart enough to have bots out there to launch something like this on people. From the sounds of it though, he's making empty threats and wants to sound geekier than I just did.

thanks guys

If xbox live handles things anything like the ps3, He can't. I'm pretty sure that the ip is only viewable from your network or a game server, and it should be different from your computers ip.

He can spoof an IP address. DoS does not require a valid return IP address, U can alter the ICMP Packet header to reflect a fake return address. only when u get the ISP involved and FBI Maybe can they maybe possible track it down, but Just a DoS on a regular citizen doesnt constitute the 10k + investment in time and money to track down the offender, if you report a problem like this to your ISP they would probably just change your IP address .. But yeah.. Technically, it is possible for them to slow you down, but unlikely.

Adding... -- Not sure about xbox live architecture either.. so most likely MS has some form of protection against them finding your IP address in the first place as mentioned above.

Nope he can't