Ugh, 2 more.
1. I uninstalled both versions of Blender, re-installed Blender 2.64 and renamed the "Blender" file within "Blender Foundation". After re-installing Blender 2.49, it still replaced 2.64. Can you please give me a more detailed answer? I'm not very advanced with computers, you know.
2. I saved my model as "Legacy Mesh Format", but I still couldn't open it in 2.49. Help?