My PC won't run when I connect the cable that runs from the phone jack to the cpu?

[mamaDee]

My internet connection (broadband) has always been slow due to the distance from my home to the Embarq line. Now, however, I have had to do a destructive recovery for about the 4th time because the computer wouldn't run at all. After doing the DR, I used the computer just as it came out of the box - no internet connection, no installed software, nothing. It seemed to do the little bit you can do with the original programs fine. As SOON, though, as I plugged the line from the phone jack to the CPU the computer started either not running at all, starting, turning off and restarting by itself, etc. As long as it's not connected to the internet it seems to be fine, but it's no good to me like that. Anyone know what the problem might be? This computer has been being connected to a Cisco broadband router along with my Mac, which is doing just fine. Incidentally, about 3 recoveries ago an Embarq help desk person had me move one of the yellow cords to another slot. What I'm referring to is the slots on the back of the router are numbered 1, 2, 3 and 4 and then you also have a slot named "Internet". I don't remember where I moved it from, but the cords are now in slots 1 and 2. Of course the blue cord is in the slot labeled "Internet".