Clearing Firefox buffers
 

I can't get to the Internet to use Tools. Trouble started yesterday when DSL line was down for about 30 min. Have been on the phone to AT&T twice. First time verified the line had been down and came back. But I had no Ethernet lights. Second call ended after rep. didn't know how to get to the FF buffers, etc. I have Linux, no Windows, so msconfig, which she suggested, didn't run. I tried to install XP on another disk, and the result is that any time I try to boot, I get an XP intro screen and then immediately a blue warning screen that says to check for viruses. Don't know what to do and now I'm back to having to use Library computers.

Nothing in your post suggests a problem in FF. Open a terminal and use ifconfig to see if you have an IP address on your ethernet port. If not, restart networking and check for errors in the messages file. Once you get an IP, try:
- ping localhost
- ping www.google.com

Post back with any error that you can't figure out.

ATT sucks I would suggest going into your router and changing the DNS nameservers from AT&Ts to either OpenDNS or Google's DNS

OpenDNS
nameserver 208.67.222.222
nameserver 208.67.220.220

Using Google Public DNS - http://code.google.com/speed/public-dns/docs/using.html
The Google Public DNS IP addresses (IPv4) are as follows:

8.8.8.8
8.8.4.4

The Google Public DNS IPv6 addresses are as follows:

2001:4860:4860::8888
2001:4860:4860::8844

You can also try editing /etc/resolv.conf and adding either OpenDNS or Google's nameservers there.

For example mine looks like this:
$ cat /etc/resolv.conf
nameserver 208.67.222.222
nameserver 208.67.220.220
nameserver 8.8.8.8