Hello. My cron jobs start at 12pm but I'd like to change the time. I'd like the processes to start earlier. How can I do that? I think I must edit the /etc/crontab file. Here is the code:

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

Could anyone please tell me the right code for starting cron jobs at 4am? Thank you.

If you aren't familiar with cron and don't want to make a mess of it, try using webmin to control it...
That might be overkill, so you could also try doing a search on google for 'cron faq' or similar.. which should give you a number of basic explanations of the syntax for cronjobs