Here's my opinion of you entire situation.
You say you've made thousands of tweaks? You make changes based on what tech support tells you at the time? It sounds to me like the whole system is FUBAR. I'd reformat and do a clean install of XP Pro on every pc on the network, or at a minimum, I'd reformat one of them, and take the others offline. I'd then hook up ONLY that pc with the new installation of XP PRO to the DirecWay connection and see what the performance is then. The next thing I'd do is create a Backup Image of that pc's hard drive, and then if you need to call tech support and they foul up the works again, then you go always Restore from the Backup Image. Clear as mud?
Good luck,
Gil
My Speed, YEE HAW!
:::.. Download Stats ..:::
Connection is:: 4011 Kbps about 4 Mbps (tested with 1496 KB)
Download Speed is:: 490 KB/sec
Tested From:: http://www.testmy.net/
Bottom Line:: 72 times faster than 56K you can download 1MB in 2.09 second(s)
Validation Link:: https://testmy.net/cgi-bin/get.cgi?Test_ID=0UANU1X0C