http://www-307.ibm.com/pc/support/si...id=HOME-LENOVO
go to that website, enter your model number (not the t42) it will be on a white sticker on the bottom of the unit, will be 4 numbers then 3 characters of numbers and letters. will look something like 6363-2AU. type that number minus the - adn press Go. click on user manuals, then click on the hardware maintenance manual. If the battery blinking is an error code it will tell you exaclty what it is in this manual.