Canon MX700 Stopped Working (running Vista)

My Canon MX700 all-in-one worked perfectly connected via USB to my Vista
Gateway laptop. In mid December I downloaded and installed the 1st public
beta of Vista SP1, and after several hours and several BSODs, I uninstalled
SP1 beta and all was well again.

Sometime afterward, when I went to use the scan function, I got the message
"Cannot communicate with scanner.....scanner is off.....not connected". Yet
all other functions worked (print, fax, copy).

I have spent hours (and days) with Canon support and you name it - we tried
it - including downloading/installing the latest Intel Vista chipset drivers.
The botom line - we can get the scanner to work again by simply deleting
the MX700 drivers and reinstalling them. That is - until any one of the 2
events happen (which again results in the above disconnect message);

1. System is rebooted (warm or cold) or,
2.. MX700 is powered down

To get the scanner to work again, I go into device manager, delete the
driver and reboot with the MX700 powered on. All the other devices and ports
on my system work just fine.

Note: Letting my system go into Hibernate, then turning the printer/scanner
off does not cause it to "diconnect".

Canon's senior techs can't figure it out so they are sending me another
MX700. Somehow, I suspect this is a software problem - maybe related to
Vista SP1 beta. Anyone else have this problem? Suggestions?

I have the same problem with my Canon Lazer printer LBP1120. I can't recall
installing the 1st public beta of Vista SP1 but was offered a vista update a
few weeks ago and agreed - was this the one? I'm trying to find the solution
- will be in touch if and when I do.