anyone a computer whizz?

ive got a djm600 with a lead going straight into my sound card on my pc... ive been recording mixes into nero for 3 yrs with no problem.

suddenly, its not recording. the cables fine as it plays from the pc when i swap it from input to output & recording out to line in on the mixer... the program is fine cuz it does everything else... it says its recording but no graphic equalizer comes up to show its getting the sound it.

ive checked everythings plugged in correctly, ive checked the recording volume on the soundcard & stuff like that but not sure what else to try!

the only thing i can think of is that we messed some volume setting up cuz we watched spiderman 2 thru pc on projector the other wk & couldnt get it to play the foreground volume so fannied around with volume settings then, but only on the dvd player programme...

appreciate any help :o)

thanks!