If you only have one computer, and it is for personal use only, I think it will not make many problems; but if you have more than one computer, and they are functionally for many users, that will be a big problem.
This case might be founded at the office, internet cafe, school, public library, public service, a computer's rental, hospital etc.
There are many computers installed over there, the question is, how to monitor all of them?.
It is not good enough to use an Antivirus to solve this case.
Because the Antivirus will only to protect your system from any change of the Operating system or document's files, but it cannot to lock or protect your system's files from any damage or fail.
If someone trying to delete all of your system's files, the Antivirus will not take any action for this event, or if someone trying to install any program to your computer and then the program makes your computer's system corrupt or fails to run, the Antivirus will not take care with that event.
That is why we need some powerful software to handle that case.
They are 3 software options to solve the above case.

1. If you are using Microsoft Windows as an operating system for your computer, you can use the features of Microsoft Windows, which was called a System Restore, you can find that features in the program menu or control panel.
   It will restore your system to the latest good setting from the restore point.
   
2. You can use Norton Ghost program to solve this case, but you need to install it first to your entire computer, and then you have to back up the system's files.
   Since this program is a backup tool for operating system's files, you need to save the backup files to another partition drive or an external disk.
   You will need these files whenever you have a computer damage or fail, then it will restore your system back, so that you will not waste your time to re-install the operating system to your computer anymore.
   
3. The last option may help you better than the other 2 options above, it is called a Deep Freeze program, you only need to install it first to your computer, and it will keep your computer protected all time.
   How does it work?.
   When your computer has been restarted, the program will restore back your computer's system to the original condition.
   If anyone has installed any software in your computer, it will be removed and cleaned after restarting computer.
   You do not need to remove it by yourself even there are many files or programs installed in your computer by any users.
   To use this program, you have to split the hard drive at least to two partitions drive, the first partition is for your computer's system files, which the Deep Freeze program will be installed to, and the second partition for the data files where anyone is able to save their files or install their program to the second partition drive.
   Also, you can use this program to prevent and against any virus, spyware or malware.
   The most important thing, when you install this program you will be asked to create a password, and you have to keep that password safely, do not forget it, because you will need that password when you want to install any program in your computer, also you cannot remove that program if you have forgotten the password.
   

When your computer has been corrupted or failed, and it cannot to be restored with any program, then the option number 2 is a better method than other options to solve that problem.
In other cases, it will be good to use all of the above options if you want.
Good luck to try!