Hello!
I just made a crazy mod. Its an Akaviri Katana that does like, 9999 shock damage. After making it, making the enchantment, applying the enchantment, placing the sword on the floor in front of The Best Defense, AND SAVED IT IN MY DATA FILES. I go and start the Oblivion Launcher to check the mod in my data files, but IT DOESNT SHOW UP.
Any suggestions? I've googled it, made the mod again, but nothing came out. It's my first mod btw...

Maybe its falling through the ground? Try to move it on top of a crate or something as the ground is very unstable. Or you could put it in a barrel since you'll be picking it up before the container respawn.

Its not that I cant see it, the .esp doesn't show up so i can actually select the mod.

It sounds like you have Windows 7 and installed Oblivion into the default directory. Install Oblivion to a directory outside of Program Files (like C:/Games/Oblivion). The problem should disappear then.

That's most likely the problem...i'll do that and check back to you. Thanks in advance!

Also be sure your game is patched to the latest official version. Using the latest CS with an older patch version of the game can also lead to mods not showing up.