Hi, RobinSmith.
See
How to uninstall Microsoft Security Essentials, which includes a link to a Microsoft Fix it solution.
I suggest that you scan your system with your on-board anti-malware software. If you don't have one installed, I suggest that you do the following:
Download
Malwarebytes' Anti-Malware to your desktop.
- Double-click mbam-setup.exe and follow the prompts to install the program.
- At the end, be sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and Launch Malwarebytes' Anti-Malware, then click Finish.
- If an update is found, it will download and install the latest version.
- Once the program has loaded, be sure Quick scan is selected, then click Scan.
- When the scan is complete, click OK, then Show Results to view the results.
- Be sure that everything is checked, EXCEPT items in System Restore as shown in this sample:

- Click Remove Selected.
- When disinfection is completed, a log will open in Notepad and you may be prompted to Restart. (See the Note below)
** Note **
If MBAM encounters a file that is difficult to remove, you will be presented with 1 of 2 prompts. Click
OK to either and let MBAM proceed with the disinfection process. If asked to restart the computer, please do so immediately.