I'm not sure if you'll read this reply or not since this topic seems a bit old but to update the drivers for your Intel 82801 PCI Bridge do the following.
Download the lastest chipset utility for your PC and save it somewhere you can easily find. (root of C: drive)
Click Start -> Run -> "path to chipset utility w/o the quotes" -a
This should extract all of the drivers from the chipset utility to C:Program FilesIntel
Now open device manager and find the Intel 82801 PCI Bridge under system devices. Right click it, choose update driver, and point it at the diectory containing all the extractedchipset drivers. (default should be C:Program FilesIntelInfInstInfAll)
I'm not sure why the chipset utility doesn't automatically update this device's drivers...
Hope that helps,