Cannot surf

I am working on a laptop that I cannot get to surf. The details are:
1. It will connect (dial-up).
2. It seems to surf for the first 1.5 to 2 seconds.
3. It stops receiving data, but it still seems to be sending.
4. It fails when I ping or tracert.
5. I have already tried the following:
a) re-install DUN
b) remove (manually) and reinstall DUN
c) use different modem
d) extract new copy of each file for DUN from original win98SE CD, and check all applicable registry setting.
e) Thurouhgh check for viruses. (none found)
f) reinstall windows. (without formating)

I am trying to fix the issue without formating, as this is for a picky customer.
Any information would be apreciated.