For some reason the driver on my Creative X-Fi sound card disables the 'Microphone +20dB Boost' option after every reboot. I wrote a script to automatically enable it every time the system boots up.

var WshShell = WScript.CreateObject("WScript.Shell");

WshShell.Run("Control.exe mmsys.cpl,@0,1")
WScript.Sleep(100);
WScript.Sleep(100);
WshShell.SendKeys("{RIGHT}");
WshShell.SendKeys("%{P}");
WScript.Sleep(100);
WshShell.SendKeys("+{TAB}");
WshShell.SendKeys("{RIGHT}");
WshShell.SendKeys("{TAB}");
WshShell.SendKeys(" ");
WshShell.SendKeys("~");
WshShell.SendKeys("~");

Save this script as micboost.js, or download it here. Drag the file into your Start->All Programs->Startup directory. This should work on Vista and 7, but probably not on previous versions of Windows.