Windows 7: Please a help with my microphone

Hello everybody
i have windows 7 ultimate x32 sp2 ..... before i was using the microphone on skype .. but after i formatted my pc ... when i speak the other cant hear me ... plz help ..

First of all, I'll need a little more information.

Have you confirmed that the device you have the mic plugged into is enabled / that Windows (or you) installed drivers for the device?

You can confirm that it is enabled this way:
Control Panel -> Hardware and Sound -> Manage Audio Devices. Click the "Recording" tab and see that your device is enabled and functioning.

If it is not enabled, try to enable it. If you don't see any devices in "Recording", you may have to right click and check "Show disabled devices".

Have you checked your skype settings to make sure that the correct listening/mic device is set as default.

Under Tools -> Options -> Audio Options. It's a drop down menu. Just select the device that you have enabled.