Drum Kicks "Overlayering" my sample. (noob)

Ok things first first i choped a sample in many parts and created a nice melody with it. Then i wanted to put the kicks/snares/hh etc. but the problem is that when i try and put the kicks the melody gets muted and the only thing that is heard are the kicks themselves. I tried to lower their volume but nothing happens. What's the problem. Maybe the quality of my sample was low?

easiest way, put the drums on a diff program than the sample.
If you have no other programs, create a blank one,
put drums on it on the same pads as the previous program and you wont have to re-record.

First off, what MPC you using? There are many different models so remember that next time when asking.

You might be using a Program that was previously used for a past song and its settings remain the same. I'm guessing that Mute Groups were left on for those sounds. Create a new Program and adjust the settings for each sample on it. Or you can just adjust the old Program.