Hi, and thank you for asking your question.
Upgrading to Windows 10 will fix some of the system issues you are having, e.g. with MS Security Essentials, but if your system has other non-related issues, like slow performance, it's a whole another process to troubleshoot and fix them, i.e. by removing junk programs, disabling startup items and services, etc.
May I connect with you remotely to carry out a comprehensive cleanup of your system now?
Please reply back to me below; thank you.