Due to deadlock , application stuck.

I have application developed with Asp.Net and MSSQL 2008 R2.

1) There are three main table handling 80% transactions
2) Insertion and Read both going on at same time for a same project.
3) For the same project multiple user insert the data and view the data.
4) While this process going on deadlock taking place and whole application get stuck
5) While we re-index it . application works for some minutes and stuck once again

I had set SET DEADLOCK_PRIORITY, Isolation Level. but position is very tough....

Pls help,