when i switch from wireframe mode back to “normal” mode at certain viewing angles the mesh turn completely black:( which makes it realy hard to see what im doing and i dont know exactly how it looks. I have put an image below so you understand what im talking about. p.s how do you undoin 2.49b because being an noob ive made alot of mistakes playing around and i keephavin to reload it. thnx, lg 
not quite sure what’s going on but in edit mode if you select all the faces (A key twice ) then press cntrl+ n the normals will recalculate to outside.
it might also be your graphics card if the black blinks on and off
for undo : cntrl+z