Supersheep's story reminds me of my story.
Comcast came out and installed all the crap and it worked (their modem, USB ether dongle). I bought a wireless router and started hooking all the stuff together on the floor.
It was like working a little, then none, then a little - for hours and hours. Since I had never set up an ethernet network before, I thought it was all software related. My friend was no help, so I suffered and finally went to sleep exhausted.
The next day I moved everything to another room and it seemed to work pretty well like 80% of the time, with occasional deep slowdowns. I always chalked these up to cable company problems.
Then one day, I was cleaning that room and the connection was sucking. My friend piched up the router which was sitting next to the cable modem and put it on the table. Since I was at the PC, I noticed a data burst after it had sat dead. I was like WTF?
We both looked at each other. He says, "Maybe the wireless router doesn't like to sit next to the cable modem" (they looked cool cooking away side by side). I was thinking - dumb theory, but said "lets see." So we hold the router at the following distances from the modem: next to, 1 ft away and 4 ft away. Results?: No data, slow data, fast data.
We repeated it several times with clear results. Without question, they could not sit near each other, and all problems were solved. The wireless router was pushing too much radiation into the cable modem chasis and overwhelming it. Arrgh. Hours that I thought were software, were simply those boxes being too close.
I called a friend who owns a computer company. He was like, "huh?" So he says "hold on" . . . tries it and his connections drops off. Then he tells me, "Thank's I'm going to tell all of my techs to keep an eye out for that!"
Since then, things have been hunk dory, and no need for any cable company help or software. The line itself has problems maybe like 1 day every couple of months.
And they all lived happily ever after