Try cleaning the battery contacts with a pencil eraser. But without knowing more about your problem I doubt anyone can help.

Here's a phone number for Nikon technical support:
800-645-6689.

I had the same problem with my D70 2 days before emegrating from the UK to Australia, took it into Nikon headquarters in Singapore and picked it up 3 days later having had the light measuring sensor replaced free of charge, as it is a known problem on the early D70. As Larry said it might be worth calling technical help with the problem. From what I can remember the fault was intermitant, one minute it would turn on and work as normal and then the next time i turned it on there would be no display or anything.

http://www.robgalbraith.com/public_files/D2H_D70_N55_Service_Advisory.pdf

Take a look at this .pdf file to see if it will help.

Cheers

Graham