Here is where you need to extract the mods to.
C:/Program Files/Data Realms/Cortex Command
If you don't know what that means then take a damn computer class.

Sorry about the angry people but their right

which mods are you trying to install?

There are a few mods on this site that aren't easy to install cause of either a stupid Windows XP or WinRAR (or a combination) bug. An example is amrobotics cool mods, they are great and install easy for some people, but others you unzip, plop the .rte into the main folder - and the mod doesn't show up in game.

In those cases, just copy the contents of the unzipped mod folder to a new folder (which you name exactly the same). Move the newly created folder to the cc directory. That's a work around for that kind of problem at least.

Posted after 4 minutes 12 seconds:

Hmm...when you unzip, are you left with just the mod.rte folder? Its not nested in another folder i.e. the name of the zip file. Is it?

when you unzip, do the filepaths look like:

mod.rte/index.ini

or

mod.rte/mod.rte/index.ini

If its the latter...then like the others said, you need help

when you install this mod, the file path to that mod's index file should look like:

cortex command/mod.rte/index.ini

Look who's talking.