Mystical problem with the output

This is really driving me crazy. I did something and i lost the sound from my project.
The ASIO drivers are normal, outputs seem active and individual tracks even show signal
but nothing is coming out to master. Other projects are working just fine so the problem
is not in the hardware or software, it’s only this one particular project.
If someone can tell me what to do to fix this, i will be forever grateful
I’m jusing cubase 5.