How can I permanently disable an intruder from my computer?

Question

Computer networks

I was not at home for about a year (I was studying), and my parents and the little one worked at a stationary computer. The problem is that some "hacker" has taken over our computer. The computer works as usual without problems, but if you step away for a while, you can see that someone controlled it, and recently he also wrote hello to us in a notebook and told us about his intentions. So how do you end this? How he could have taken possession of it at all, the little one does not admit to anything. What should be removed or what should I do so that he can no longer control my computer? Comp on windows 7.

Answer 1

Options:
1. Disconnect your computer from the Internet.
2. If the computer is connected via a router, enable firewall on it.
3. Check the computer for viruses, for example, using KVRT
4. Remove programs for remote access to the computer, such as Remote Administrator, TeamViewer (if any). Or remove all programs that seem suspicious to you.
5. Reinstall Windows.

Answer 2

Despite the fact that I am not an information security specialist, in my opinion there are the following risk factors:

1. low awareness on the topic of information security - it is useful to visit sites like https://www.SecurityLab.ru at least periodically
   
2. router (router) settings with default admin password (admin/admin, admin/12345, etc.)
   
3. router settings with remote access .
   
4. router settings with weak WEP-type authentications, weak passwords, etc.
   
5. router settings with open ports for anything and everything, as well as other network settings
   
6. old router with old firmware
   
7. unlicensed installed OS downloaded from the Internet
   
8. uninstalled or not installed on time regular OS security updates
   
9. any software installed from dubious sources (especially games)
   
10. lack of OS protection tools: antivirus (at least built into the OS) and firewall
    
11. Software not updated in time (holes in Adobe Acrobat Reader, Adobe Flash, Java JRE, etc.)
    

Answer 3

1. Call an IT friend you know and give him a bottle)
2. Remove the network cable, there will be no Internet, but also entry points.
3. Block access to Remote Assistance, Remote Desktop, uninstall teamviewer, radmin.

Answer 4

Demolish Windows to hell with disk formatting. This is if you want fast.

Answer 5

Initially, take a port scanner and check which one works. Throw away what is clearly yours. Close whatever is left. And most importantly, start with the router.
We turn off the Internet, run wireshark, remove all the packages that are. And look at the sub-hot activity.

Answer 6

but if you don’t move away for a long time, it’s clear that someone controlled him, and recently he also wrote hello to us in a notebook and told us about his intentions

it is clear that he has visual information and he sees whether someone is sitting at the computer or not.
I think that someone from the family is joking)

Answer 7

install kaspersky free
change password if wifi and turn off WPS
update firmware in router
change admin in router to any login