Normally when I turn the mains power switch on, the monitor turns on (green) then it goes on standby (orange). The CPU remains off (as usual). Now, when I turn on the mains power switch, the CPU turns on automatically and I can hear the fan running but the monitor doesn't turn on (light remains orange). Even if it doesn't turn on automatically, when I do turn it on the monitor still won't turn on. After rebooting and switching the power off and on multiple times it eventually works, but what is wrong with the CPU? (I don't think it is the monitor's fault as it does work perfectly fine eventually).
PS I'm not very confident in opening the CPU and handling the hardware inside.