I am a bit new to this but I had an idea to add an LED light to a portable CD player that would come on when the CD started playing. I opened up the case and found a switch that detects if the lid is opened or closed. If the lid is detected as closed, the CD player will power up and begin playing. I wanted to add an LED light that would come on whenever the lid was closed. However up until this point I have only wired LEDs in where there is a larger power source that is easily accessible and the circuit was not hampered with other things (the components on the board of the player). Again, I am fairly new to this so maybe this isn't a huge issue. The CD player runs on 4.5v and I have it working with either batteries or an AC adapter. Can this be accomplished with the voltage that low? Not to mention with all the other components in there. I am thinking if I wire it somewhere around that lid switch it might work but I don't know where to draw power from.
Will you have room for an Arduino in there ?
Nope, no arduino this time.
Wrong forum then my friend...
Yes, you can do that - if you can figure out how ("aye, there's the rub.")
A couple or several milliamps for an LED probably won't tank your player.
You need to know what that switch does exactly.
Does it switch a voltage to GND ?
Or does it switch a power line (less likely) ?
Once you know that, you can figure out whether you need an extra transistor or not.
You should also consider to use high efficiency LEDs, which only need something like 2 mA instead of 20 mA, and so save you some battery time.
MAS3:
You need to know what that switch does exactly.
Does it switch a voltage to GND ?
Or does it switch a power line (less likely) ?
Once you know that, you can figure out whether you need an extra transistor or not.
You should also consider to use high efficiency LEDs, which only need something like 2 mA instead of 20 mA, and so save you some battery time.
Thank you so much for the guidance. I really appreciate it. This will get me headed in the right direction. I really like the idea of having my player glow blue through the window in the lid while it is playing. Knowing that it is possible gives me hope I will eventually get it figured out.
Oh, and Boffin, thanks for absolutely nothing! So glad you could grace us with your presence regardless. We're not worthy! 
As a matter of fact, Boffin1 i think is right with his remark about the wrong forum part.
As your question is about LED and this part of the forum is called LEDs and multiplexing, i think you might have thought this to be right.
However, General Electronics would have been the better choice in this case.
But that doesn't mean your questions shouldn't be answered if possible.
So if you have any more questions, just ask.
A moderator might move this thread to another forum part if they decide that to be more suitable.