So I get another tower from a friend, is a HP pavilion a1101n. I have HP monitor and keyboard from previous system. Comcast Internet with Motorola modem sb5120 and a net gear router. Xp home. issues are now that all networking connections are showing connected, yet unable to access Internet. Keyboard is not functioning, and does not see this modem,. Have tried all the unplugs and replugs, outside of calling Comcast, I'm stuck.