I also have the XPS420 (intel chipset) and had the same error. I got the driver package and it took a couple of installs and reboots for it to stick. As a convenience, you can download that package here:
http://uswave.net/windows7/intel-smbus-drivers.zip
Just extract the files into the folder of your choice, then goto the device manager and update the driver. You have to tell it to manually locate the driver, just put in the drive/folder name where you unzipped the file. Like I mentioned, it took a couple of installs/reboots for the driver to "stick" to the smbus.
I hope this helps (tip my scales)
I also have the XPS420 (intel chipset) and had the same error. I got the driver package and it took a couple of installs and reboots for it to stick. As a convenience, you can download that package here:
http://uswave.net/windows7/intel-smbus-drivers.zip
Just extract the files into the folder of your choice, then goto the device manager and update the driver. You have to tell it to manually locate the driver, just put in the drive/folder name where you unzipped the file. Like I mentioned, it took a couple of installs/reboots for the driver to "stick" to the smbus.
I hope this helps (tip my scales)
just installed the latest INF chipset updater drivers from intel (v9.1.0.1012) and it worked perfectly. no compatibility mode required.
I also have the XPS420 (intel chipset) and had the same error. I got the driver package and it took a couple of installs and reboots for it to stick. As a convenience, you can download that package here:
http://uswave.net/windows7/intel-smbus-drivers.zip
Just extract the files into the folder of your choice, then goto the device manager and update the driver. You have to tell it to manually locate the driver, just put in the drive/folder name where you unzipped the file. Like I mentioned, it took a couple of installs/reboots for the driver to "stick" to the smbus.
I hope this helps (tip my scales)

Have you checked the action centre? Sometimes it picks up the sm bus issue.
i was just posting in another thread about this. here is the link to the correct driver:
Confirm Download
if you need to install in compatability mode then it's not the correct driver.
however, since upgrading to 7068 and now 7077 it seems to have been included in the base install, 3 intel PC/laptops i've tried anyway.