M-Audio, Fast Track Pro & Ableton LIVE 6

[projectfusion]

I have come across a bizzare problem. I was running M-Audio, Fast Track Pro with Ableton Live as a traditional DJ setup for few weeks. The way it was connected was 1 Audio in Live was routed to channel 1/2 through Audio To: Ext Out and 2 Audio in Live was routed to channel 3/4 in similiar way. Now from Fast Track Pro, I connected 1/2 rca to one channel of the mixer and 3/4 rca to the other channel of the mixer. So basically its a traditonal dj setup using Live, Fast track pro and my mixer. Then yesterday i started the pc and i dont get any sound from channel 3/4. I have tried the cue function within live as well but channle 3/4 doesnt work. I have tested the card on a different software but still no luck. I have been told by Fast Track Pro support team that it is an IRQ conflict. What could be the problem? I have tried disabling the onboard souncard on my laptop but still no luck. Today it started working all of a sudden for few mintues then i turned Fast Track Pro and laptop off and then tried to get it working but again its not working.