You could set your isolation level to Serializable but it will make everything else slower
run a trace on the server and look for the deeadlocks
also look into trace flags 1204 and 1205
also if you have 2 statements in a batch make sure that they are in the same order
tran 1
update table a
update table b
tran 2
update table b
update table a
things like this will cause a deadlock
Inside SQL Server 2000 has an excellent chapter on locking/blocking
http://sqlservercode.blogspot.com/