Is Problem Windows, or Imaging?

For some time now, I have been unable to open graphic files on my hard drive. When I try to do so, with a right click or left click, I get a message Error starting program - a required .dll file TWAINPP was not found. I have tried uninstalling the scanner software - and gone into regedit and deleted references to Canon and found TWAIN files and deleted it and then reinstalled the software - nothing has worked. Now, I wonder if I should run a restore of the original system software. The Canon scanner won't work any more either even with downloading and installing newest drivers from their website. All help greatly appreciated.
Norm72

Your scanner has NOTHING to do with not being able to open pictures on your computer.

If you right click and select open with->try MS Paint and see what happens.

Steve,
First thanks for your post. After your suggestion, I did use Paint and was able to open many of the files - those that ended with file extension jpg, but not gif's. And I can not attach these graphic files to e-mail messages as I could previously - actually I can, but after attaching - I get the same error message when trying to open / work with them. I also have an WIA on the system from installation of a digital camera - could that be conflicting with TWAIN? Really, I am asking how to correct the problem that is causing the error? If I search and find all the TWAIN files and delete them - and the WIA file - and then run a Restore - without formatting - - do you think that will correct the problem?
By the way, I have WinME on a SONY VAIO 40GB HDD, 368RAM, AMD AThlon, 1GB processor.
Lastly, I really appreciate any and all help I receive.
Norm72