pc freeze after boot time scan

hi! my pc with windows vista freeze after a boot time scan. it happens when the scan is finished, or at least it seems so, and when windows is rebooting a black screen appared and the pc freeze and a force shutdown is required.
anyway i’m not sure the scan is completly finished when it happens.

Check the log file at what point it “freezes” and let us know.
Could be a large/encrypted file that takes a long time to scan and make it look like the system is frozen.

which log? what folder is it in?