lost dhcp!

Just upgraded my access payroll, and my network server
won't work!

OK, machine is Windows 98 (1st release) all patched
applied, clean install yesterday.

two network cards, one with hard IP for internal network,
one dhcp assigned for router, winproxy configured to
provide a bridge for users to access the net etc.

all was well until I installed access payroll v9, the new
one for tax year to apr 2005. The proxy lost touch with
the external net card, using ipconfig, I found the address
to be 0.0.0.0

transfered router and proxy software to a similarly
configured machine, and it works.

need to know what part of windows the payroll has killed -
which component does the lookup and assignement of an ip
to a network card from a dhcp server?

thanks Ian