A couple of things come to mind. When you went into the bios were the hard 
disk and floppy disk recognized? If not it may be worthwhile to check the 
cables especially the floppy because it is very easy to have these reversed 
in some way. Second, when you replaced the battery, was the computer 
completely off and disconected (PSU plug). I had a problem  with an old 
computer of this vintage, when I replaced the battery and did not have it 
completely disconnected, AND you also have to allow time for the caps to 
discharge! The bios did not bother to look around for the hardware that it 
figured it already had in the cmos. This took me days to figure out, with 
some help from a forum or two. It may just have been a problem with my old 
dell or it may be a problem with some bios' of this vintage.

Good luck
Art

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