Major help needed w/ Sound rEcorder

Hi
Well, I couldn' make audacity work so i stupidly asked my housemate to see if he could do anything w/ it. An hour later I found him messing with microsoft Soudn Recorder (how the F did he get there????) which i had working before he messed with it, so now I can't record anything! I'm not even getting feedback on playback anymore, there is just NOTHING! All other computer sound works fine. I tried setting vol back where I though it was with 'line in' selected & all the way up & other volumes turned down. Nothing.
There used to be a button to test it, which i can't find now. That's how I magically got it working the first time. Windows XP.
HELP!!:crybaby