I seem to have lost the Version tab when I right-click .exe or .dll files and select Properties. I now just get the tabs: General, Compatibility, Security and Summary.
Running a fully-patched Windows XP SP3.
Some DLLs do not include a version resource, thus no Version tab. Try the same thing with a DLL in your Windows\System32 directory. Are you sure you've lost that Version tab for all DLLs/EXEs?