You’ve got three main choices to back up your computer
If you have to restore your whole computer, you will typically need to create a rescue disc or a USB stick with software to boot into to copy over your backup.
I prefer the ease of backup software such as EaseUS versus Windows Built-in Backup. Research your options as your particular needs are different on a case-by-case basis.
This step is important in case any of the optimizations mess up your system.
Some Startup Apps are found directly in your Startup Folder from your Start Menu’s Program Files.
If you click the Start button, then All Programs, you’ll be able to scroll to find the Startup Folder. You can right-click to delete the link to the apps that you don’t want to start automatically when you log on to your computer. This won't delete them from your computer as long as it is just the shortcut.
You could also remove hidden startup apps using special directions for editing your Windows registry, but editing the wrong part of your registry can mess up your computer a bit. Do that at your own risk.