Networking :: unpredictable net connect on many attempts

Hi all,
I'm running DSL on an acer laptop EXTENSA 711TE (PII, 128MB ram), with CD image, I must use fb1024x768 at startup for properly setting video. At the first install (liveCD install) I configured PPPoE and I succesfully connected to internet via PMCIA netcard (realtek). After HD install I lost the connection. I reconfigured PPPoE and I never reconnected on many configuration attempts. Also rerunning liveCD was unhelpful. So I reformatted hda2 then rerun liveCD configured PPPoE and all run fine. Then I backup on hda3, do HD install and restore. Nothing. I reformatted hda2 and rerun liveCD. Nothing working. I' frustrated. Please help. If I will reconnect how can I safely backup network configuration? Which files should I edit to see network config details, so I can check them?

original here.