I don't believe my line from the outside of my house is bad(from the
green Telephone Network Interface box, i.e. ATT/Bell hardware that
brings in my phone line to my house). I've worked as a cable
installer/tech for a few years, I have all the cable tools, BTW I have
one of those security keys to open the box, basically a 5/32" allen
wrench with a hole in the middle, you can make one by cutting halfway
into a allen wrench but you can get them on ebay relatively cheap, too.

I ran in all the cat5 cable from the interface box into my room,
terminated everything and also I share the line with my phone and my
phone works okay when I'm not on the internet. So basically the
wiring is new and the connections are good, to the best of my knowledge.

I have a Windoze box and I don't have any problems, and I use the same
external modem and I use some of the same cable, albeit on the other
side of the room. Of course, if nothing else can solve it, I will
swap out the phone lines from the 2 computers to see if there is a
difference. I doubt it, as I have one of those cheap Cat5 cable
testers you can get on ebay for a few bucks, and my connections are okay.