Laptop Optimization and Security Installation

I'm currently facing multiple challenges with my electronics which require immediate assistance.

Firstly, my Windows laptop is operating slower than usual, frequently displaying a rotating blue circle which suggests to me that the system is always busy. On top of this issue, I cannot successfully load free antivirus software on it as the installation process continuously fails. I need someone proficient with Windows systems who can troubleshoot and resolve these problems.

Secondly, I have purchased two security cameras and a video doorbell which need to be set up. I'm looking for assistance on both their installation and configuration to ensure they function perfectly and provide the intended security.

The ideal freelancer for this project should have:
- A strong understanding and experience in troubleshooting Windows laptops
- Knowledge on antivirus software installation
- Experience in setting up security cameras and video doorbells.

Assistance in this project entails not only solving existing problems, but also preventing future ones similar to what I'm experiencing currently. I would appreciate a freelancer who's willing to explain the procedures for future reference.