Copy this into notepad and save it as a VBS file. It should be ran from a local admin account and will set the log size at 2.5MB, overwrite to 14 days. You may change the log size and or overwrite time. Hopefully if it stays set, you may then try to manually set it to overwrite as needed.
strComputer = "."
Set objWMIService = GetObject("winmgmts:" _
& "{impersonationLevel=impersonate,(Security)}!\\" & _
strComputer & "\root\cimv2")
Set colLogFiles = objWMIService.ExecQuery _
("Select * from Win32_NTEventLogFile")
For each objLogfile in colLogFiles
strLogFileName = objLogfile.Name
Set wmiSWbemObject = GetObject _
("winmgmts:{impersonationLevel=Impersonate}!\\.\root\cimv2:" _
& "Win32_NTEventlogFile.Name='" & strLogFileName & "'")
wmiSWbemObject.MaxFileSize = 2500000000
wmiSWbemObject.OverwriteOutdated = 14
wmiSWbemObject.Put_
Next