Hello Alan, There a a few steps in this guide that should help you.
Please follow our Removal Guide here Remove Security Shield
After reading how the malware is misleading you ...
You will move to the Automated Removal Instructions
After you completed that, post your scan log here,let me know how things are.
The log is automatically saved and can be viewed by clicking the Logs
tab in MBAM.
Copy and paste the contents of that report in your next reply. Be sure to post the complete log to include the top portion which shows MBAM's database version and your operating system.