My laptop inbuilt mic works fine in things such as Camera (windows 8) or 'set up a mic' but it does not work in FL Studio! I have gone through all of the inputs in the mixer but none work! Please help!
Try switching between all your audio soundcards in FL Studio's audio settings. Typically the built-in/primary sound driver should support the mic
You have to use the ASIO4ALL (or FL ASIO in FL Studio 12) driver. Then in the driver's control panel make sure you have the input enabled (but don't worry, it should be by default).
Example (it can differ from your configuration): http://forum.cockos.com/attachment.php?attachmentid=17741&d=1363618063
Then, in a mixer's channel, select your device at the INPUT section. See: