Fortigate 80C stopped, need help.

Hi there, I an newbie here. Just got a problem for 80C. It stopped working occasionally, nobody could go to internet. When I login it show on Dashboard that Registration unreachable. AntiVirus, IPS and Vulnerability Scan all failed. CPU usage was around 95% high. When click on CLI Console it shows Connected but with error: Cannot read termcap database, using dumb terminal setting. All log file are missing. When I tried to reboot it just hang. I have to disconnect the power and wait for a few minutes. after trun it on normally it works fine. Checked the log after restarting, it stopped logging anything sometime a few hours ago. It seems this more often since this January. I am not good at Fortigate and CLI. If you have any ideas about this issue I am glad to hear. Thank you. The screenshot is below.