How do I make my Computer Protected and working fastly?

You don't have to do anything.., just

1. Install good and free antivirus (i prefer Microsoft Security Essential)

2. Install Removeable Disk Autorun Removel like USB Disk Security

3. Uninstall unnecessary software

4. Cleanup your PC with any Utility like CCleaner

   ---> Also think to upgrade your PC's hardware

we can Never use the Internet or check your e-Mail without Anti-Virus Software installed we have to install anti-virus to protect the computer and make it work fast and save