WIA windows image acquisition service won't cannot start - help! (stisvc)

I have a Canon PowerShot SD450 which XP only recognizes as a USB still camera.  It doesn't show up as a drive letter, and the camera & scanner wizard does not start when I plug it in.  Installing ZoomBrowser EX did not help, since it also does not see the camera.

 

I have a CanoScan N656U scanner, for which I install the Toolbox.  I can scan, but the button on the scanner no longer starts the toolbox.

 

Both of these products used to work fine until I reinstalled a fresh Win XP SP2 onto a new HD.

 

After lots of searching, I found the my WIA service (stisvc) is not running, and won't start.  When I try to start it, I get error 1053 that it wouldn't start.

 

All dependent services are running as far as I can tell, and the camera does not need a driver accorning to Canon's website.  I spent two days searching for an answer online, but can't find any info about this.

 

How do I get my WIA service to start?

 

thanks.