Ubuntu 12.04 Freezes and Need Troubleshooting Help

[keen]

Thank you in advance for helping! The following is my issue.

I'm using Ubuntu 12.04 LTS Desktop, ISPConfig (Perfect Server - Apache2), Linux, on an HP Proliant. Server freezes up when not being pinged or used. Where can I start troubleshooting?

I've removed a lot of the desktop programs (Firefox, Thunderbird, Gwibber, Gedit, etc,) on Ubuntu to see if that was the cause, however, that didn't help.


EDIT: I also installed the Linux server headers via the apt repository.