I tried several times to Windows 7 System Restore my machine, with self defence option off, but after each failed restore, the option was somehow switched on again, now I do not whether this option was switched on during the (failed) restore, got several warnings: “Restore Failed try other restore point” after reboot, anyways I had a blue-screen-of-death and all restore points gone, even the avast ones.
http://members.tele2.nl/galien8/Images/avast_selfdefence.jpg