I never had that problem before. Waht could be the problem?
I restarted it and installed updates. Once the updates were installed, I restarted again. Both times I restarted It looked like when the kernal started it went into emergency mode. It told me to check the log with journalctl -xb.
Here are some of the errors in the logfile. It easier than pasting the whole log file into Pastebin.
acpi LNXCPU:00: Invalid PBLK length [7]
ACPI PCC probe failed.
tpm_tis 00:05: A TPM error (7) occurred attempting to read a pcr value
fsck failed with error code 4.
Can't find host 0.ubuntu.pool.ntp.org: Name or service not known
Can't find host 1.ubuntu.pool.ntp.org: Name or service not known
Can't find host 2.ubuntu.pool.ntp.org: Name or service not known
Can't find host 3.ubuntu.pool.ntp.org: Name or service not known
Can't find host ntp.ubuntu.com: Name or service not known (-2)
no servers can be used, exiting
nm_device_get_device_type: assertion 'NM_IS_DEVICE (self)'
PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.s
PAM adding faulty module: pam_kwallet.so
[1426604909.775168] [dns-manager/nm-dns-dnsmasq.c:
[pulseaudio] pid.c: Daemon already running.