Slow intermittent service ISP says I have many ip address

[rwbruce]

So working with my ISP to figure out why my speed goes up and down during downloads and terrible pings in games and they said i had about 30 ip address coming from my computer and thus with so many using bandwidth my service is slow. So ran 4 different virus checkers and nothing still lousy service and i have no clue what i am doing. Windows 7 everything up to date...before I reformat my hard drive and start over any idea's ? why would I have so many IP address?
Help someone i am so frustrated

 

[Emerald]

how many devices are connected to your network?

is your router secured via wireless password?

 

[rwbruce]

right now only my main computer. Everything else has been disconnected from the router. It is password protected.
I live in the country so no one close enough to be trying to use my wireless.
Since i am in the country i am connected via a radio receiver type of device..sorry forgot whats it called. It sits on top of the roof pointed to the ISP's tower. I realize its not going to be the fastest way of getting internet but right now my speeds are so up and down it s worse than dial up.