MySQL Is Frequently Down

I have a VPS with following features: Dual Xeon, 512MB Ram (up to 1GB), CentOS.
Unfortunately MySQL is frequently down, about once per day, and it takes time to set up again. to change mysql config to resolve this issue?

my.cnf:

PHP Code:

[mysqld]
skip-bdb
max_connections = 250
max_user_connections = 30
thread_concurrency = 1

key_buffer = 128M
myisam_sort_buffer_size = 32M
join_buffer_size = 1M
read_buffer_size = 1M
sort_buffer_size = 1M
record_buffer = 1M

max_allowed_packet = 8M

table_cache = 200
thread_cache_size = 64

wait_timeout = 10
connect_timeout = 10
interactive_timeout = 10
max_connect_errors = 10

query_cache_type = 1
query_cache_limit = 1M
query_cache_size = 8M

skip-locking
safe-show-database

#log-slow-queries = /var/log/mysqld.slow.log
#long_query_time = 2

[mysqld_safe]
open_files_limit = 8192

[mysqldump]
quick
max_allowed_packet = 16M

[myisamchk]
key_buffer = 64M
sort_buffer = 32M
read_buffer = 16M
write_buffer = 16M