HI, one of my servers crashes every night. My logs look OK. What should I look for to narrow it down? I need to find out what the problem is ASAP

If you know when it is happening every night, sit down with "top" at that time and look for unusual processes and/or resource usage.

You can also check your crontab to see if there are any jobs that are setup to run around the time your server goes down. The job might be taking down your server, and that can explain why it is happening around the same time every night.

what is the mobo and nic card types / models

Redhat 7.2? Some system stuff runs at 4am everymorning and half the time it crashes my clients box, could be the same thing.