I am a blender noob running 2.40 on MacOSX 10.3 Panther.
I was going through a tutorial on making a head and got into a wierd UI issue.
After trying to merge two objects into one I found that there was only an “Object” mode in the Mode list!!! The “Edit Mode”, “Vertex Paint”, etc modes were all gone. :-\
When I open Blender the modes are all there but as soon as I open the project file I was working on they all disappear but the “Object Mode”.
It seems that the UI setup must be stored in the .blend file.
If anyone has any ideas or pointers to help me get to the default UI I’d be eternally grateful
Although you should still be able to access modes with Hot Keys, your best bet is probably to start a new project in 2.40 and use Shift-F1 to load the data from that old .blend file into your new one.