Okay, so I've bought a new Lenovo Notebook a month ago, then I bought a Razer Carcharias Headset.
A couple a days ago some friends started complaining that they don't hear me in Skype Calls, so I started investigating the issue. As I looked up further I found that my microphone's 3.5mm jack in which the headset was plugged into was not picking up any noise from the microphone. I immediately tried a different headset - same thing.
I looked up in Google - there have been many differents topics on the matter, but none of them solved my case.
For your reference , my PC Specs are :
Intel Core i7-4700MQ 2.4GHz/3.4MHz
Windows 8 64-Bit OS
8GB DDR3 1600 MHz
1TB (1000GB) 5400rpm SATA
NVIDIA 2x GeForce GT 750 SLI with 4GB GDDR5
plus an Realtek HD Audio card which used an Realtek HD Audio Manager Program to manage its resources.
I used all the boosts that are available and all the workarounds around that Manager Program, but none of them worked. In the end, I ended up by boosting my mic input, but also getting an awful ammount of noise, which made the boosting irrerlevant.
So, the answer to all these problems is pretty simple :
Go to Add or Remove Programs, then remove all Realtek Programs and Drivers you can find, then use your Windows Default ones. This is the thing which solved it for me. And as I didn't find anything useful on the internet, I decided to share this and make it useful with users who have the same problem.