Samsung SCX-3405W Scanner Not Working

[Bilvihur]

The scanner light move partway across the window, then stops. It was working normally last week. Can someone give me an idea how to troubleshoot the problem? Thanks.

 

[Bilvihur]

Update:
I can get into Tech Mode (+ + stop - - stop stop), select SA, and exercise the scanner. It move freely across the glass. Selecting EL it prints the Error Log which says I had Fuser Low Heat Error at some time (but I'm not printing). The instructions say to download the EDC program, but the only EDC I find is the Easy Document Creator, and the display looks nothing like the what shows in the Tech manual. I CAN print a test page successfully.
Samsung Printer Diagnostics says it cannot connect to the Scanner. Troubleshooting says to enter Error Code Display Mode (power + - power power), but I can't get any codes to display, either in Tech Mode or idle.
I would appreciate any advice/suggestions on where to go from here. Thanks.

 

[Bilvihur]

After taking the side covers off and checking the electrical components and connections, I decided to give it one last shot:

I uninstalled all the Samsung drivers and applications, cleaned the registry, and deleted all references to Samsung on my computer. Then I did a clean install of the drivers and software for the printer. Some of the scanner software was in the Easy Document Creator, and some was in the Easy Print Manager. Then I ran diagnostics successfully, and son-of-a-bitch! - the scanner works!