Yesterday, after visiting a website that may not have been secure, I found my Windows Security Center was turned off. Shortly after this McAfee removed a trojan from my computer. After doing a scan of my computer I re-opened Security Center. When I clicked "Turn on now" it said "The Security Center service can't be started". Following another thread's advice I did Start > Search 'services' > Security Center (which has nothing under Status and Disabled under Start-up type) > Properties and though I could change Disabled to Automatic (Delayed Start) when I clicked OK and re-clicked Properties it had turned itself back to disabled. Also, under Service Status it says Stopped, yet I cannot click Start.
I also found that Windows Firewall was not using the recommended settings. When I click Update Settings it says "Windows Firewall was unable to make the requested updates". Clicking 'Turn Windows Firewall on or off' a box saying "Windows Firewall settings cannot be displayed because the associated service is not running. Do you want to start the Windows Firewall service?" I click yes and it opens the settings box however it says I am using the recommended settings.
To add to my problems, clicking on Windows Defender on the side menu brings up this message: "Application failed to initialize: 0x800106ba. A problem caused this program's service to stop. To start the service restart your computer or search Help and Support for how to start a service manually". Since then my computer has been restarted twice and still no luck.
Lastly, whether it is a connected issue I'm not sure, however my Windows Live Messenger, when attempting to sign in, will begin to load, then stop working and close itself. Restarting didn't help this either.
Any advice at all on what might have caused this or how to fix any of these problems would be greatly appreciated.