Need help - FreeAgent how to turn the led off?

I've had a few Seagate Freeagent enclosures over time, I didn't think the LED could be turned off...it should go out when you put your Mac to sleep, though. If it really bothers you, you could pop the case open, void your warranty and unplug the little twisted wire running to the LED, then it won't ever turn on.

(I should tell you, I never load or run any of the manufacturer's software that comes with these things--I delete it and reformat the drive with Disk utility--so I might not be the best person to advise you.)

I tend to be very low tech with leds, I just put a piece of electrical tape over the things.

My solution of choice as well. If you want to get fancy, cut the tape down to the exact size with a pair of scissors, and often it looks totally normal. Electrical tape comes in a variety of colors... just a few bucks at Home Despot for a multicolor pack.