Mf4570dn will not scan

[Shelly]

I have a Canon Image class MF4570dn printer/scanner that will not scan - it did scan up to a few weeks ago and i can't figure out what is wrong - I have shut it down and checked all the cables.  I am working on windows 7 Professional - when I try scanning it goes into thinking mode forever or sometimes I get an error message stating something about the computer.

[Jengan]

My Cannon MG3520 used to give me a visual picture of whether my printer/scanner was "selected" or not. I can't find tha now. The  I want to scan documents and something is interfering. Windows put upgrades on last week. I didn't have trouble before that. What do I need to check or readjust?