You might try changing the file properties to "Overwrite as needed"
Else possible the *.evt file(s) are corrupt. Control Panel|Administrative
Tools|Services|Event Log Service|General, set the "Startup Type:" to
"Disabled" restart the pc, then delete (or move) the corrupt *.evt file(s)
from %windir%\system32\config then set the Event Log Service "Startup Type:"
back to "Automatic", restart for effect.