XP doesn't have native drivers for all devices, therefore after reinstalling windows, you need to reinstall the chipset drivers, the video driver, bluetooth driver, and some others. I'd start with the chipset drivers as that may include the bluetooth drivers. If not, you need to find the make/model of the bluetooth chip/hardware and go to the manufacturer's web site to find the driver.
XP doesn't have native drivers for all devices, therefore after reinstalling windows, you need to reinstall the chipset drivers, the video driver, bluetooth driver, and some others. I'd start with the chipset drivers as that may include the bluetooth drivers. If not, you need to find the make/model of the bluetooth chip/hardware and go to the manufacturer's web site to find the driver.