I am sorry to hear you are having problems to get the chipset driver but let me guide you.
It is important to say that Intel® provides the hardware to Computer Manufacture and they will design and create their computers with special limitations according to their computer design. Due to this, the driver for the chipset in your computer can be downloaded from the Lenovo only but checking the board specifications, it seems there are drivers for Win 7 and Win 8/8.1 but no XP.
My best recommendation is to contact Lenovo directly and verify with them if is possible to get this driver for XP specifically for your system
Here is their contact information: