Start-up hangs at Building DMI pool

This started after installing USB ports in a socket 7 system. had some intermittent problems with the Isa channel 2 controller prior to this and was working on that before the client needed usb immediately for Digital camera. Have tried boot from floppy but system not finding command.com . Should I sys the C drive again?
(system is rebuilt with only Windows 98 on it but client has misplaced his 98 CD so can’t reload – don’t want to wipe HD and start over for this reason.