PC sees internal network but cant get out to the internet

Ive tried all the likely stuff. unintalling, reinstalling. Unit is running DHCP on a 98SE system. "PATIENT" explains that after running ad-aware and rebooting, system would not get out on to the internet. didnt do an *un-do* option for the ad-aware thing, anyhow - not ure why this would effect it. Anyone want to give process for me to try on this beastass.