Finding viruses after new install

I just formatted and installed XP Pro on a computer. As soon as I put the Charter.net cable modem to it for Internet my virus software went off telling me that I have a rootkit and five other warnings about viruses or spyware that it found. I have SP2 on the XP and Avast antivirus. Avast went off about 30 seconds into my checking my Favorites like Microsoft.com, MSN, and a .gov website.

This is the second time that this has happened to this computer in a month. Fresh format and install and plugging into the Net.

Is this something attacking Charter.net? At the location where I have done the install and as Verizon as dsl on the same computer I get no virus/spywares found.

What's up with this Charter?

Was the fire wall active? I do not think so and without it, with in 15 seconds of hitting the internet, the computers is infected.

Do you have a router?

This pc was not mine but was plugged right into the modem straight and the firewall was off. But how come I was on with Verizon for three hours and nothing. Click into Charter's cable modem and one website and the junk comes in?

That just shows you how many hackers were on Charter at the time versus how many were on Verizon at the time. Tomorrow, it could be the other way around.