You are correct, it was a kernel problem and not KDE 4.5. I looked back at my updates and noticed that kernel 188.8.131.52 was updated to 184.108.40.206 the day before I did the KDE 4.5 update. While I had tried kernel 220.127.116.11 without any luck, I went back to kernel 18.104.22.168 and all is working fine with the Broadcom interface on the Dell's. As for the ACER with the Atheros interface, i was able to use kernel 22.214.171.124. However, that I had to delete the 70-persistent-net.rules file you suggested and start over again to get it running.
Thank you very much for you assistance in getting this resolved. I hope I can return the favor someday.