Help i need to disable my alarm!!!

My van has been driving just fine intill yesterday?I went to start it up and it wouldn't turn over?So i figured it was the starter so i replaced it and when i hooked it all back up i had the same problem and the alarm keeps going off so now it has drained my battery and i don't know what to do????Please help me i feel so helpless!

What year villager, is it factory installed alarm system? disconnect the battery. Does the alarm use a remote for keyless entry. If so try locking the van and reopening it using the key, using the key should take the alarm out of the ciruit.

Do you think the alarm was preventing the van from starting to begin with?