Scanner problem

i hv 2 all in 1 machines. (canon mf310 , canon mp280) all the functions of machines were worked properly with window 7. But suddenly scan function stop for both of machines. printing and copying function is fine. uninstalling and reinstalling of all the drivers and updating of drivers could not fix the problem. nothing happens .
any solution or suggestion .........???????????

reinstall windows 7 and also check for scanner service in servies. twain drivers and services.

Simple used canon mp280 disk nala driver kar lao nahi power la k usb att pc and auto scaan for driver on net