Pentax K100d problem

[Pentaxpete]

I just pulled my K100 out of the closet, put fresh batteries, lithium rechargeable AA in it and all hell broke loose. Battery depleted warnings, unable to go through settings but did manage to shoot about 40 pics with flash before it went back to "Battery depleted. Every time I turn it on there's a different battery level shown and nothing works consistently. I changed the batteries to fresh charged Nimh and got the same results.The camera has been unused for about 8 years and was working perfectly when I pulled the batteries and put it in the closet. So any ideas anyone?