if you've gone through several batteries, and they always fail shortly after putting them in... and assuming they are the correct type of battery, then i would think one of 2 things to be the problem
1) motherboard circuitry at fault... how old in the board? do you see signs of age (bulging caps, etc?)
2) there is a short between the board and the case standoff... pull the board and make sure they all line up with the install holes, etc..
Q6600 quad @ 3.2
X-FI Extreme Music Sound Card
Zalman 9700 HSF