Pls give more details or errors...check your /var/log/syslog or /var/log/messages...
The closest that I could find as far as errors are concerned came from the "syslog" file as follows -
Jan 24 22:20:30 vector kernel: [52162.890308] CPU0: Core temperature above threshold, cpu clock throttled (total events = 10303878)
Jan 24 23:00:13 vector gdm-binary[2738]: WARNING: gdm_slave_xioerror_handler: Fatal X error - Restarting :0
Jan 24 23:00:15 vector kernel: [54547.250835] NVRM: GPU at 0000:01:00: GPU-51c55a9a-f995-2c59-134b-3f4a9dfd67b2
Jan 24 23:00:16 vector gdmgreeter[28711]: GLib-CRITICAL: g_key_file_get_boolean: assertion `key_file != NULL' failed
Jan 24 23:00:16 vector gdmgreeter[28711]: GLib-CRITICAL: g_key_file_get_string: assertion `key_file != NULL' failed
Jan 24 23:00:16 vector gdmgreeter[28711]: GLib-CRITICAL: g_key_file_get_string: assertion `key_file != NULL' failed
Jan 24 23:00:16 vector gdmgreeter[28711]: GLib-CRITICAL: g_key_file_get_locale_string: assertion `key_file != NULL' failed
Jan 24 23:00:16 vector last message repeated 5 times
Jan 24 23:00:16 vector gdmgreeter[28711]: GLib-CRITICAL: g_key_file_free: assertion `key_file != NULL' failed
Jan 24 23:00:28 vector pulseaudio[28840]: [pulseaudio] pid.c: Stale PID file, overwriting.