How to get a list of enabled mods ?
There are a few ways to create a list of currently used mods.
One method consists in using the command prompt of Windows to create a list of .esm and .esp files in your Oblivion/Data folder. The method itself is described in details in the Oblivion Mods FAQ section of the The Elder Scrolls Wiki.
The second method is provided by a program especially designed for this purpose - Super Simple Mod List Generator ... which is really a batch script of the commands listed in the first method. The problem with these two methods is that they will include mods that are not currently activated, as long as they are in the Data folder.
For a more accurate list of active mods, the last method is a by-product of Oblivion Mod Manager (OBMM). Install it and run it at least once.
The plugins.txt file created by OBMM is located in :
C:\Documents and Settings\[username]\Local Settings\Application Data\Oblivion