Meeb,
With Win98 you can install on top of itself to refresh your system. That never fixes any problems. Having a clean Hard Drive and installing from the CAB files is the only way to get a fresh install of Win98.
If that is what you did, then the problem is a problem with either with the DNS Entries for your internet connection or your Firewall not allowing webpages. If you can surf with a different browser then there is a problem with the setup of IE. Did you put a checkmark in the IE setup to automatically detect settings? (It is in the LAN Options.)
Take Care,
Richard