Quote: "does it need phantom power or a pre-amp?"
phatom power is for some condenser mics, i doubt he will though because he sasys that he has plugged it into his sound card so i would guess its a 1/8th plug not an xlr jack needed for phatom (and yes i know you can use a stero 1/4 as a balanced output)
my best guess would be that it's impedence is too high for your soundcard, it would be nice to know what type of mic it is and who it is made by (i'm guesssing its a dynamic made by some small company for karoke)
amd athlon xp 2600+,1280mb,FX 5200 128mb,200gb & 120gb,xp pro sp2