Ubuntu trusty Crashing

I have been dealing with linux on and off. I recently installed Ubuntu trusty 14.04 to использовал it туз в Веб and ftp server.

however intermittently i believe my system is crashing. I have not been able to see it myself. I leave the system up and running and when i ест back to office the next day its shutdown.

I have enabled the GUI, I am not sure how relevant that is.

I researched and figured out I should be looking at sylog and kern logs. I switched on my system today at 4:51:37 Dec 24. after seeing it down.

**Syslog:**

Dec 23 10:33:01 indcucmserver dhclient: DHCPREQUEST of 10.77.184.10 on p4p1 to 10.77.184.9 port 67 (xid=0x7325624f)
Dec 23 10:33:01 indcucmserver dhclient: DHCPACK of 10.77.184.10 from 10.77.184.9
Dec 23 10:33:01 indcucmserver dhclient: bound to 10.77.184.10 -- renewal in 33599 seconds.
Dec 23 10:39:01 indcucmserver CRON[14803]: (root) CMD (  [ -x /usr/lib/php5/maxlifetime ] && [ -x /usr/lib/php5/sessionclean ] && [ -d /var/lib/php5 ] && /usr/lib/php5/sessionclean /var/lib/php5 $(/usr/lib/php5/maxlifetime))
Dec 23 11:09:01 indcucmserver CRON[14886]: (root) CMD (  [ -x /usr/lib/php5/maxlifetime ] && [ -x /usr/lib/php5/sessionclean ] && [ -d /var/lib/php5 ] && /usr/lib/php5/sessionclean /var/lib/php5 $(/usr/lib/php5/maxlifetime))
Dec 23 11:17:01 indcucmserver CRON[14918]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)

**Dec 24 04:51:37** indcucmserver rsyslogd: [origin software="rsyslogd" swVersion="7.4.4" x-pid="680" x-info="http://www.rsyslog.com"] start




**Kern logs**

Dec 23 07:06:14 indcucmserver kernel: [84838.816981] audit: type=1400 audit(1450834574.308:73): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/lib/cups/backend/cups-pdf" pid=14052 comm="apparmor_parser"
Dec 23 07:06:14 indcucmserver kernel: [84838.816989] audit: type=1400 audit(1450834574.308:74): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=14052 comm="apparmor_parser"
Dec 23 07:06:14 indcucmserver kernel: [84838.817324] audit: type=1400 audit(1450834574.312:75): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=14052 comm="apparmor_parser"
Dec 24 04:51:37 indcucmserver kernel: [    0.000000] Initializing cgroup subsys cpuset

It seems like server did not print anything before crashing. Хан you please help and guide я further. I just cannot afford the server to крах every now and then.

Regards, Адарс Чохан