Hi Guys I really need your help, I have downloaded 3 mods recently, namely Elven Weaponry, Elvenguard, and the Woodland Rangers. Every one of the mods adds new armors/weapons, and whenever I encounter on of those new items, all I see everywhere is yellow or they are invisible.

I have the steam version of oblivion, with the patches, all DLC, and my other mods that do not add any new content work fin (e.g. Better Cities)

Heres my load order:

Oblivion.esm
Better Cities Resources.esm
Adonnays Elven Weaponry.esp
Elfenwacht.esp
Woodland Rangers.esp
DLCShiveringIsles.esp
Knights.esp
Better Cities Full.esp
Better Imperial City.esp
Better Imperial City FPS Patch.esp
Better Cities.esp

I

I have a Intel Core i7 2.00 GHz processor with a 64-bit Operating System, my computer is almost brand new. I have also had this problem with Fallout 3, but it was fixed with archive invalidation, maybe the same fix could be applied here?

Please help!!!!!!

You have missing res. You installed all BC bsa ? Why "BetterCity.esp" is such low. Check you have all bsa, use BOSS.

Edited :
I'm sorry I was too chaotic.
1. Uninstall your mods. With DLC exception.
2. Use some mod organizer/installer. The best - Wrye Bash. Use bsa redirection feature.
3. Install UOP and UOPsi ( with supplements )
4. Install your mods.
5. Use BOSS.

It happened before I had better cities though too, when I just had those three mods

Wait sorry How did I get here from the Skyrim forum um.. Sleep typing? anyways forget what I said

The yellow blocks are caused by missing meshes (caused by putting the files in the wrong directory), or installing new .bsa files without using archive invalidation.

Wrye Bash is an excellent mod manager and takes care of archive invalidation.wkomarecki's advice is good, uninstall your mods, get wrye bash and reinstall them using it.

I re-installed the elvenguard mod into the the data files, Its just 2 folders for meshes and textures and the .esp, then checked it in Wrye Bash, but the exact same wthing happened

Hmm, try following these steps from http://devnull.sweetdanger.net/archiveinvalidation.html

Start Wrye Bash.
Click Replacers tab.
Click the Update button under Archive invalidation.
Quit Wrye Bash

Also, http://www.tesnexus.com/downloads/file.php?id=10724 has worked well for me in the past

If that doesn't work, and your file structure is correct, I'm not sure what the problem might be.

Exactly. Check Elvenguard, and the Woodland Rangers what you have installed and what you should have out . Maybe these mods structure is "data\meshes..," instead just "meshes\...".
Wrye Bash allows you have your res. over control, if you install all mods via Bain. You may use wizard scripts for more complicated to install mods. Use it.