There are likely several CMOS settings that will heep a computer from booting. One of the most obvious is the password setting. If you make it require a password to boot the computer, it won't boot. Then there are the hard drive settings. If you disable the hard drive or the hard drive ports, then the computer won't boot. Then there are settings that should never be used for this, such as setting the memory and CPU clock to very unreasonable values.
Do not connect to the internet.
Enter a password, either administrator, user, or drivelock. The last, commonly available on laptops, will prevent your hard disk from being read by any other computer if removed from yours.
To prevent virus in computer you can use some antivirus apps and being very careful about clickable links.
When it is first turned on from being off for awhile.
gat a trusted security group and avoid spam
You can't. Unless you physically hacked the chatroom, you can't actually stop yourself being booted. You'll just have to keep going back to that chatroom.
Because your computer is being stupid.
To prevent being struck by lightning:Don't use cellphone or electronic gadget when its lightning.Don't use a computer when lightning is in the area.Don't use a landline phone when lightning is in the area.Stay inside during a thunderstorm.
Get a good protector for your computer that blocks viruses (I suggest Norton) and don't visit websites that seem sketchy
"All computers have spyware which is mostly used by hackers.You can prevent spyware by being educated about spyware, the computer and third the internet connection."
yes they can because if you freeze water that doesn't prevent you from being able to change the water back into its original state
To prevent being struck by lightning:Don't use cellphone or electronic gadget when its lightning.Don't use a computer when lightning is in the area.Don't use a landline phone when lightning is in the area.Stay inside during a thunderstorm.