Start-Run-Regedit
There could be more than one "AdvancedTab" value.
Try these keys first and then search for AdvancedTab (no space)
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet
Explorer\Control Panel
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet
Explorer\Control Panel
Remove "AdvancedTab" if present.
Do the same for "SecurityTab".
You should also investigate the possible parasite that removed the
tabs.
....Alan